Package 'dtametaTMB'

Title: Diagnostic Test Accuracy Meta-Analysis using Template Model Builder
Description: Fits the hierarchical summary receiver operating characteristic (HSROC) model of Rutter and Gatsonis (2001) <doi:10.1002/sim.942>, the bivariate binomial-normal model of Reitsma et al. (2005) <doi:10.1016/j.jclinepi.2005.02.022>, the threshold-based bivariate time-to-event model of Hoyer et al. (2018) <doi:10.1002/jrsm.1273>, and the latent class extensions of Liu et al. (2015) <doi:10.1111/biom.12264> for diagnostic studies with an imperfect reference standard. Provides subgroup analyses, HSROC meta-regression, likelihood-ratio tests, summary ROC plots, and coupled forest plots.
Authors: Claus Nowak [aut, cre]
Maintainer: Claus Nowak <[email protected]>
License: GPL (>= 2)
Version: 0.1.3.9000
Built: 2026-10-19 20:22:05 UTC
Source: https://github.com/ebme-uwk/dtametatmb

Help Index


Anaemia Synthetic Dataset

Description

This is a synthetic dataset where haemoglobin was measured by a point-of-care device, with laboratory measurement acting as the reference standard. Lower values indicate disease (anaemia).

Usage

anaemia

Format

A data frame with 81 rows and 11 variables:

study

Study identifier

threshold

Haemoglobin in g/dL

TP

Number of true positives

FN

Number of false negatives

FP

Number of false positives

TN

Number of true negatives

D

Number of diseased individuals

H

Number of healthy individuals

sens

Sensitivity

fpr

False positive rate

testdirection

Smaller values indicate disease (=less)

Source

Synthetic dataset.


Likelihood Ratio Tests for Diagnostic Test Accuracy Models

Description

Compare nested diagnostic test accuracy meta-analysis models using likelihood ratio tests (LRTs).

Usage

## S3 method for class 'Reitsma'
anova(object, ..., test = "Chisq")

## S3 method for class 'RutterGatsonis'
anova(object, ..., test = "Chisq")

Arguments

object

A fitted model object.

...

Additional fitted model objects to be compared.

test

Character string specifying the test to perform. Currently, only "Chisq" is supported.

Details

These methods compute likelihood ratio statistics from the fitted model log-likelihoods and compare models ordered by increasing numbers of estimated parameters. The test statistic is

−2(ℓ0−ℓ1)-2(\ell_0 - \ell_1)

where ℓ0\ell_0 and ℓ1\ell_1 are the log-likelihoods of two nested models. Under standard regularity conditions, the statistic follows a chi-squared distribution with degrees of freedom equal to the difference in the numbers of estimated parameters.

The models supplied should be nested and fitted to the same dataset. Warnings are issued when models have identical numbers of parameters or when the log-likelihood decreases for a more complex model, suggesting that the nesting assumptions may be violated.

Value

An object of class "anova" inheriting from "data.frame" with the following columns:

Df

Number of estimated parameters in the model.

logLik

Model log-likelihood.

Df.diff

Difference in parameters compared with the previous model.

Chisq

Likelihood ratio chi-squared statistic.

Pr(>Chisq)

P-value from the chi-squared test.

Caution for variance-component tests

The usual chi-squared reference distribution requires appropriate regularity conditions. In particular, these conditions may not hold when the null hypothesis constrains one or more random-effects variance components to zero, because variances are non-negative and zero lies on the boundary of the parameter space.

This issue can arise when comparing Reitsma models that constrain sigma2_A or sigma2_B, or Rutter-Gatsonis models that constrain sigma2_alpha or sigma2_theta. Tests involving multiple variance components constrained to zero may require additional care. In such cases, the asymptotic reference distribution may be a mixture of chi-squared distributions rather than a single chi-squared distribution. The appropriate distribution depends on the model and the constraints being tested.

The implementation uses the ordinary chi-squared reference distribution and does not apply a boundary-adjusted reference distribution. Therefore, the reported p-values may not be appropriately calibrated for tests of variance components on the boundary.

References

Self, S. G. and Liang, K. Y. (1987). Asymptotic properties of maximum likelihood estimators and likelihood ratio tests under nonstandard conditions. Journal of the American Statistical Association, 82, 605–610.

Stram, D. O. and Lee, J. W. (1994). Variance components testing in the longitudinal mixed effects model. Biometrics, 50, 1171–1177.

See Also

logLik(), anova()


Anticcp Dataset

Description

This is the anticcp dataset from Nishimura (2007) from a review of anti-cyclic citrullinated peptide antibody (anti-ccp) to diagnose rheumatoid arthritis.

Usage

anticcp

Format

A data frame with 37 rows and 7 variables:

study

Study identifier

year

Year of the study

TP

Number of true positives

FP

Number of false positives

FN

Number of false negatives

TN

Number of true negatives

generation

First generation (CCP1) or second generation (CCP2) assay

Source

Nishimura, K. et al. (2007). Meta-analysis: diagnostic accuracy of anti-cyclic citrullinated peptide antibody and rheumatoid factor for rheumatoid arthritis. Annals of Internal Medicine, 146(11), 392-403. doi:10.7326/0003-4819-146-11-200706050-00008


Export Model Results for RevMan

Description

Converts fitted model objects (Reitsma, ReitsmaSubgroup, RutterGatsonis, RutterGatsonisSubgroup, ReitsmaLCA, ReitsmaSubgroupLCA, RutterGatsonisLCA, and RutterGatsonisSubgroupLCA) into a format suitable for manual entry into the Diagnostic Test Accuracy module of Review Manager (RevMan).

Usage

as_revman(x, ...)

## S3 method for class 'Reitsma'
as_revman(x, ...)

## S3 method for class 'RutterGatsonis'
as_revman(x, ...)

## S3 method for class 'ReitsmaSubgroup'
as_revman(x, ...)

## S3 method for class 'RutterGatsonisSubgroup'
as_revman(x, ...)

## S3 method for class 'ReitsmaLCA'
as_revman(x, ...)

## S3 method for class 'RutterGatsonisLCA'
as_revman(x, ...)

## S3 method for class 'ReitsmaSubgroupLCA'
as_revman(x, ...)

## S3 method for class 'RutterGatsonisSubgroupLCA'
as_revman(x, ...)

## S3 method for class 'ReitsmaSubgroupTMB'
as_revman(x, ...)

## S3 method for class 'ReitsmaTMB'
as_revman(x, ...)

Arguments

x

A fitted model object.

...

Currently not used.

Value

A data frame with columns:

Subgroup

Only returned for subgroup model objects.

Externally_Calculated_Parameters

RevMan model/parameter types.

Parameter

RevMan parameter name.

Estimate

Parameter estimate.

The returned table contains the model parameters displayed by RevMan:

  • E(logitSe)

  • E(logitSp)

  • Var(logitSe)

  • Var(logitSp)

  • Cov(logits)

  • Corr(logits)

  • Lambda

  • Theta

  • beta

  • Var(accuracy)

  • Var(threshold)

  • SE(E(logitSe))

  • SE(E(logitSp))

  • Cov(Es)

  • Studies

Note

For Rutter and Gatsonis models SE(E(logitSe)), SE(E(logitSp)), and Cov(Es) are not computed.


Extract Model Coefficients

Description

Returns the estimated model parameters.

Usage

## S3 method for class 'DTAmodel'
coef(object, ...)

## S3 method for class 'Reitsma'
coef(object, ...)

## S3 method for class 'ReitsmaSubgroup'
coef(object, ...)

## S3 method for class 'ReitsmaLCA'
coef(object, ...)

## S3 method for class 'ReitsmaSubgroupLCA'
coef(object, ...)

## S3 method for class 'ReitsmaSubgroupTMB'
coef(object, ...)

## S3 method for class 'ReitsmaTMB'
coef(object, ...)

Arguments

object

A fitted model object.

...

Not currently used.

Value

A named vector of parameter estimates.

Note

For ReitsmaSubgroup models, coef() returns parameter estimates from the cell-means parameterization rather than treatment-contrast coefficients.

See Also

vcov.dtametaTMB()


Dementia Dataset

Description

This is the dementia dataset from Harrison et al. (2015) from a review of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) for the diagnosis of dementia within a secondary care setting.

Usage

dementia

Format

A data frame with 13 rows and 17 variables:

author

Author of the study

year

Year of the study

TP

Number of true positives

FN

Number of false negatives

FP

Number of false positives

TN

Number of true negatives

rob_PS

Risk of bias: Patient selection

rob_IT

Risk of bias: Index test

rob_RS

Risk of bias: Reference standard

rob_FT

Risk of bias: Flow and timing

ac_PS

Applicability: Patient selection

ac_IT

Applicability: Index test

ac_RS

Applicability: Reference standard

Threshold.cat

Threshold category

Country.cat

Country category

IQCODE.cat

Informant Questionnaire on Cognitive Decline in the Elderly category

reference.cat

Reference category

Note

The data were taken as provided from the MetaBayesDTA application.

Source

Cerullo, E. et al. (2023). MetaBayesDTA: codeless Bayesian meta-analysis of test accuracy, with or without a gold standard BMC Medical Research Methodology 23(127). doi:10.1186/s12874-023-01910-y

Harrison, J. et al. (2015). Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) for the diagnosis of dementia within a secondary care setting.. Cochrane Database of Systematic Reviews 3. doi:10.1002/14651858.CD010772.pub2


Diabetes Dataset

Description

This is the diabetes dataset from the supplementary material in Hoyer (2018).

Usage

diabetes

Format

A data frame with 124 rows and 9 variables

study

Study identifier

threshold

Threshold HbA1c used to derive TP, FN, FP, TN

TP

Number of true positives

TN

Number of true negatives

FP

Number of false positives

FN

Number of false negatives

D

Number of diseased individuals

H

Number of healthy individuals

originally_published

Whether the data threshold/row was used in the original publication (1=yes, 0=no)

Source

Hoyer, A., Hirt, S., Kuss, O. (2018). Meta-analysis of full ROC curves using bivariate time-to-event models for interval-censored data. Research Synthesis Methods, 9(1), 62-72. doi:10.1002/jrsm.1273


dtametaTMB: Diagnostic Test Accuracy Meta-Analysis using Template Model Builder

Description

Functions for fitting diagnostic test accuracy (DTA) meta-analysis models using Template Model Builder (TMB).

Details

Implemented methods

  • Reitsma model

  • Rutter-Gatsonis HSROC model

  • Hoyer multiple-threshold model

  • Latent class analysis for studies with an imperfect reference standard

Main workflow

  • fitReitsma() -> print() -> summary() -> plot() -> forest()

  • fitReitsmaTMB() -> print() -> summary() -> plot() -> forest()

  • fitReitsmaSubgroup() -> print() -> summary() -> plot() -> forest()

  • fitReitsmaSubgroupTMB() -> print() -> summary() -> plot() -> forest()

  • fitRutterGatsonis() -> print() -> summary() -> plot() -> forest()

  • fitRutterGatsonisSubgroup() -> print() -> summary() -> plot() -> forest()

  • fitHoyer() -> print() -> summary() -> plot() -> forest()

  • fitReitsmaLCA() -> print() -> summary() -> plot() -> forest()

  • fitReitsmaSubgroupLCA() -> print() -> summary() -> plot() -> forest()

  • fitRutterGatsonisLCA() -> print() -> summary() -> plot() -> forest()

  • fitRutterGatsonisSubgroupLCA() -> print() -> summary() -> plot() -> forest()

Included datasets

  • anaemia

  • anticcp

  • diabetes

  • dementia

  • FENO

  • pap

  • RF

  • schuetz

  • tub

See the package vignettes for worked examples and model descriptions.

Author(s)

Maintainer: Claus Nowak [email protected]

Authors:

See Also

Useful links:


FENO Dataset

Description

This is the FENO dataset from Schneider (2017) from a review of fractional exhaled nitric oxide (FeNO) for diagnosis of asthma.

Usage

FENO

Format

A data frame with 150 rows and 7 variables:

study

Study identifier

study_id

Study identifier (numeric)

cutoff

Threshold for FeNO measured in ppb

TP

Number of true positives

FN

Number of false negatives

FP

Number of false positives

TN

Number of true negatives

Note

The data are reproduced from the original source and the supplementary material accompanying the Cochrane Handbook. However, the study 'Schneider 2013' contains inconsistent diseased counts (TP + FN). To illustrate the Hoyer analysis in the vignette, we modify the TP counts in rows 118–120 from 39 to 38. Other corrections restoring internal consistency are also conceivable.

Source

Schneider, A. et al. (2017). A novel statistical model for analyzing data of a systematic review generates optimal cutoff values for fractional exhaled nitric oxide for asthma diagnosis. Journal of Clinical Epidemiology, 92, 69-78. doi:10.1016/j.jclinepi.2017.09.001


Fit Threshold-Based Bivariate Time-to-Event Model (Hoyer)

Description

This is a high-level wrapper that performs the full workflow for fitting the Hoyer AFT model:

  1. Restructuring of threshold-based data into interval format

  2. Estimation of initial parameter values

  3. Model fitting via likelihood maximization

The input data must contain cumulative counts for true positives, false positives, false negatives, and true negatives at multiple thresholds within each study.

Usage

fitHoyer(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  threshold,
  smallest,
  largest,
  testdirection = c("greater", "less"),
  eval_threshold = NULL,
  conflevel = 0.95,
  dist = "loglogistic",
  verbose = FALSE,
  ...
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

threshold

The observed threshold value (column name). Must be positive and strictly increasing within each study.

smallest

Positive lower bound used to define the leftmost interval. Must be smaller than minimum threshold.

largest

Positive upper bound used to define the rightmost interval. Must be greater than maximum threshold.

testdirection

Direction of the test. Enter "greater" when larger test values indicate disease. Conversely, enter "less" when lower test values indicate disease (e.g. anaemia-type tests). Defaults to "greater".

eval_threshold

Optional numeric value or vector specifying the prediction grid threshold(s) at which sensitivity and specificity should be evaluated. If NULL (default), the median threshold from the original data is used.

conflevel

Confidence level for confidence intervals for sensitivities and specificities at the chosen thresholds. Defaults to 0.95.

dist

Character string specifying the parametric distribution for the AFT model. One of "weibull", "lognormal", or "loglogistic" (default).

verbose

Whether TMB optimization output should be printed (default: FALSE).

...

Additional arguments (unused).

Details

Fits the threshold-based bivariate accelerated failure time (AFT) model for diagnostic test accuracy (DTA) meta-analysis as described by Hoyer et al. (2018). The model is estimated using interval-censored likelihoods via Template Model Builder (TMB).

The function internally calls:

Missing values in the input data are removed prior to analysis. A message is issued listing the affected studies.

Value

An object of class "HoyerAFT" as returned by fitHoyerAFT, containing:

data

Processed original data

restructured

Interval-formatted data

fit

Optimization output

sdreport

TMB report object

sdreport2

Summary of reported parameters

sensspec

Sensitivity and specificity estimates

Note

Requires a compiled TMB model named "Hoyer".

References

Hoyer, A., Hirt, S., Kuss, O. (2018). Meta-analysis of full ROC curves using bivariate time-to-event models for interval-censored data. Research Synthesis Methods, 9(1), 62-72. doi:10.1002/jrsm.1273

Examples

data("diabetes")
fit <- fitHoyer(
  data = diabetes,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study,
  threshold = threshold,
  testdirection = "greater",
  smallest = 2,
  largest = 10
)
summary(fit)

Fit Threshold-Based Bivariate Time-to-Event Model (HoyerAFT)

Description

Fits a bivariate accelerated failure time (AFT) model for diagnostic test accuracy (DTA) data using interval-censored likelihoods as described in Hoyer et al. (2018). The model is estimated using Template Model Builder (TMB) with study-specific random effects.

Usage

fitHoyerAFT(
  data,
  init,
  conflevel = 0.95,
  eval_threshold = NULL,
  verbose = FALSE
)

Arguments

data

A list as produced by restructure_data, containing:

restructured

Interval-formatted data

original

Processed original data with derived quantities

init

A data frame of initial parameter values as produced by initHoyerAFT.

conflevel

Confidence level for confidence intervals for sensitivities and specificities at the chosen thresholds. Defaults to 0.95.

eval_threshold

Optional numeric value or vector specifying the prediction grid threshold(s) at which sensitivity and specificity should be evaluated. If NULL (default), the median threshold from the original data is used.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Details

The model reports logit-survival quantities, which correspond to sensitivity and false positive rate for testdirection = "greater", and to false negative rate and specificity for testdirection = "less".

Model fitting is performed using nlminb, and uncertainty estimates are obtained via TMB::sdreport. Parameter transformations include log-scale parameters and Fisher's Z-transform for correlations.

Value

An object of class "HoyerAFT" containing:

data

Processed original data

restructured

Interval-formatted data

fit

Optimization output from nlminb

sdreport

TMB report object from sdreport

sdreport2

Summary of reported parameters

distcode

Distribution code used in the model

sensspec

Sensitivities and specificities at the chosen thresholds

Note

Requires a compiled TMB model named "Hoyer".

References

Hoyer, A., Hirt, S., Kuss, O. (2018). Meta-analysis of full ROC curves using bivariate time-to-event models for interval-censored data. Research Synthesis Methods, 9(1), 62-72. doi:10.1002/jrsm.1273

Examples

data("diabetes")
res <- restructure_data(
  data = diabetes,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  threshold = threshold,
  study = study,
  smallest = 2,
  largest = 10
)
init <- initHoyerAFT(res$restructured)
fit <- fitHoyerAFT(res, init)
summary(fit)

Fit the Reitsma Model

Description

Fits the Reitsma bivariate random-effects model for diagnostic test accuracy (DTA) meta-analysis using a binomial-normal likelihood via glmmTMB.

Usage

fitReitsma(data, TP, FP, FN, TN, study, constrain = NULL, conflevel = 0.95)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

constrain

Optional character string specifying a simplified covariance structure for the Reitsma model.

This can be useful for sparse data, small meta-analyses, or for reproducing simplified bivariate models described in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Allowed values are:

NULL

The standard unconstrained Reitsma model is fitted.

"sigma_AB"

The covariance between logit-sensitivity and logit-specificity random effects is fixed at zero. Random effects remain independent.

"sigma2_A"

The between-study variance of logit-sensitivity is fixed at zero. This also implies a zero covariance.

"sigma2_B"

The between-study variance of logit-specificity is fixed at zero. This also implies a zero covariance.

"all"

All random-effects variance and covariance parameters are fixed at zero, resulting in a fixed-effects model.

conflevel

Confidence level for confidence intervals. Default is 0.95.

Value

A list of class "Reitsma" with components:

  • data: the original data set with derived quantities

  • glmmTMB: fitted model object.

  • estimates: parameter estimates with SE.

  • vcov: variance-covariance matrix.

  • sensspec: sensitivity and specificity estimates.

  • LRDOR: Diagnostic odds ratio and likelihood ratios.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • constrain: Random effects parameters fixed at zero.

References

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitReitsma(
  data = anticcp,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study
)
summary(fit)

Fit the Reitsma LCA Model

Description

Fits the Reitsma latent class model for diagnostic test accuracy (DTA), allowing for an imperfect reference standard under conditional independence.

Usage

fitReitsmaLCA(
  data,
  y11,
  y10,
  y01,
  y00,
  study,
  conflevel = 0.95,
  constrain = NULL,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

y11

Number testing positive with both index and reference tests (column name).

y10

Number testing positive with index test but negative with reference test (column name).

y01

Number testing negative with index test but positive with reference test (column name).

y00

Number testing negative with both index and reference tests (column name).

study

Study identifier (column name).

conflevel

Confidence level for confidence intervals. Default is 0.95.

constrain

Optional character string specifying a simplified covariance structure for the index test of the Reitsma LCA model.

Allowed values are:

NULL

The standard unconstrained Reitsma model is fitted.

"sigma_AB.index"

The covariance between logit-sensitivity and logit-specificity random effects is fixed at zero. Random effects remain independent.

"sigma2_A.index"

The between-study variance of logit-sensitivity is fixed at zero. This also implies a zero covariance.

"sigma2_B.index"

The between-study variance of logit-specificity is fixed at zero. This also implies a zero covariance.

"all"

All random-effects variance and covariance parameters are fixed at zero, resulting in a fixed-effects model.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Value

A list of class "ReitsmaLCA" with components:

  • data: the original data set with derived quantities.

  • fit: Optimization result from nlminb.

  • sdreport: TMB standard report.

  • sdreport2: Summary of reported parameters.

  • vcov: variance-covariance matrix of reported parameters.

  • sensspec: sensitivity and specificity estimates.

  • prevref: Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

  • LRDOR: Diagnostic odds ratio and likelihood ratios.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • constrain: Random effects parameters fixed at zero.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitReitsmaLCA(
  data = anticcp,
  y11 = TP,
  y10 = FP,
  y01 = FN,
  y00 = TN,
  study = study
)
fit
summary(fit)

Fit the Reitsma Subgroup Model

Description

Fits the Reitsma bivariate random-effects model with a single categorical covariate for diagnostic test accuracy (DTA) meta-analysis using a binomial-normal likelihood via glmmTMB. The model is fitted twice, once using treatment-contrast coding with a reference subgroup and once using the cell-means parameterization.

Usage

fitReitsmaSubgroup(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  subgroup,
  constrain = NULL,
  sensspec_constrain = NULL,
  variances = c("common", "unequal"),
  conflevel = 0.95
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

subgroup

A single categorical study-level subgroup variable (column name).

constrain

Optional character string specifying a simplified covariance structure for the Reitsma model.

This can be useful for sparse data, small meta-analyses, or for reproducing simplified bivariate models described in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Allowed values are:

NULL

The standard unconstrained Reitsma model is fitted.

"sigma_AB"

The covariance between logit-sensitivity and logit-specificity random effects is fixed at zero. Random effects remain independent.

"sigma2_A"

The between-study variance of logit-sensitivity is fixed at zero. This also implies a zero covariance.

"sigma2_B"

The between-study variance of logit-specificity is fixed at zero. This also implies a zero covariance.

"all"

All random-effects variance and covariance parameters are fixed at zero, resulting in a fixed-effects model.

These random-effects simplifications are currently only available for variances="common".

sensspec_constrain

Optional character vector specifying restrictions on subgroup-specific logit-sensitivity and/or logit-specificity parameters.

This can be useful for testing whether subgroup differences are present in sensitivity, specificity, or both.

Allowed values are:

"sens"

Constrain all subgroup-specific logit-sensitivity parameters to be equal. Subgroup differences are therefore only allowed in logit-specificity.

"spec"

Constrain all subgroup-specific logit-specificity parameters to be equal. Subgroup differences are therefore only allowed in logit-sensitivity.

Both constraints may be specified simultaneously, e.g. sensspec_constrain = c("sens", "spec"), which forces all subgroup-specific sensitivity and specificity parameters to be equal across subgroups.

If NULL (default), separate sensitivity and specificity parameters are estimated for each subgroup.

variances

Whether the between-study random-effects variance-covariance matrix should be assumed to be "common" (default) or "unequal" across subgroups. If "common", a single between-study variance-covariance matrix is estimated and shared across all subgroups. If "unequal", subgroup-specific variance-covariance matrices are estimated.

conflevel

Confidence level for confidence intervals. Default is 0.95.

Value

A list of class "ReitsmaSubgroup" with components:

  • data: the original data set with derived quantities.

  • glmmTMB_mu: fitted model object with cell means parameterization.

  • estimates_mu: parameter estimates with SE with cell means parameterization.

  • vcov_mu: variance-covariance matrix with cell means parameterization.

  • sensspec: sensitivity and specificity estimates.

  • glmmTMB_nu: fitted model object with dummy/reference-cell parameterization.

  • estimates_nu: parameter estimates with SE with dummy/reference-cell parameterization.

  • vcov_nu: variance-covariance matrix with dummy/reference-cell parameterization.

  • LRDOR: Diagnostic odds ratios and likelihood ratios.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • subgroups: The subgroup levels used in the model fit.

  • constrain: Random effects parameters fixed at zero.

  • sensspec_constrain: Whether sensitivities/specificities are assumed common across subgroups.

  • variances: Variance structure used in the fitted model.

References

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitReitsmaSubgroup(
  data = anticcp,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study,
  subgroup = generation
)
fit
summary(fit)

Fit the Reitsma Subgroup LCA Model

Description

Fits the Reitsma latent class model with a single categorical covariate, allowing for an imperfect reference standard under conditional independence.

Usage

fitReitsmaSubgroupLCA(
  data,
  y11,
  y10,
  y01,
  y00,
  study,
  subgroup,
  constrain = NULL,
  sensspec_constrain = NULL,
  variances = c("common", "unequal"),
  prev_variances = c("common", "unequal"),
  conflevel = 0.95,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

y11

Number testing positive with both index and reference tests (column name).

y10

Number testing positive with index test but negative with reference test (column name).

y01

Number testing negative with index test but positive with reference test (column name).

y00

Number testing negative with both index and reference tests (column name).

study

Study identifier (column name).

subgroup

A single categorical study-level subgroup variable (column name).

constrain

Optional character string specifying a simplified covariance structure for the index test in the Reitsma LCA model.

Allowed values are:

NULL

The standard unconstrained Reitsma model is fitted.

"sigma_AB.index"

The covariance between logit-sensitivity and logit-specificity random effects is fixed at zero. Random effects remain independent.

"sigma2_A.index"

The between-study variance of logit-sensitivity is fixed at zero. This also implies a zero covariance.

"sigma2_B.index"

The between-study variance of logit-specificity is fixed at zero. This also implies a zero covariance.

"all"

All random-effects variance and covariance parameters are fixed at zero, resulting in a fixed-effects model.

These random-effects simplifications are currently only available for variances="common".

sensspec_constrain

Optional character vector specifying restrictions on subgroup-specific logit-sensitivity and/or logit-specificity parameters for the index test.

This can be useful for testing whether subgroup differences are present in sensitivity, specificity, or both.

Allowed values are:

"sens"

Constrain all subgroup-specific logit-sensitivity parameters to be equal. Subgroup differences are therefore only allowed in logit-specificity.

"spec"

Constrain all subgroup-specific logit-specificity parameters to be equal. Subgroup differences are therefore only allowed in logit-sensitivity.

Both constraints may be specified simultaneously, e.g. sensspec_constrain = c("sens", "spec"), which forces all subgroup-specific sensitivity and specificity parameters to be equal across subgroups.

If NULL (default), separate sensitivity and specificity parameters are estimated for each subgroup.

variances

Whether the between-study random-effects variance-covariance matrix of the index test should be assumed to be "common" (default) or "unequal" across subgroups. If "common", a single between-study variance-covariance matrix is estimated and shared across all subgroups. If "unequal", subgroup-specific variance-covariance matrices are estimated.

prev_variances

Whether the between-study random-effects variance for logit prevalence should be assumed to be "common" (default) or "unequal" across subgroups. If "common", a single between-study variance is estimated and shared across all subgroups. If "unequal", subgroup-specific variances are estimated.

conflevel

Confidence level for confidence intervals. Default is 0.95.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Value

A list of class "ReitsmaSubgroupLCA" with components:

  • data: the original data set with derived quantities.

  • fit: Optimization result from nlminb.

  • sdreport: TMB standard report.

  • sdreport2: Summary of reported parameters.

  • vcov: variance-covariance matrix of reported parameters.

  • sensspec: sensitivity and specificity estimates.

  • prevref: Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

  • LRDOR: Diagnostic odds ratio and likelihood ratios.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • subgroups: The subgroup levels used in the model fit.

  • constrain: Random effects parameters fixed at zero.

  • sensspec_constrain: Whether sensitivities/specificities are assumed common across subgroups.

  • variances: Variance structure used in the fitted model.

  • prev_variances: Prevalence variance structure used in the fitted model.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitReitsmaSubgroupLCA(
  data = anticcp,
  y11 = TP,
  y10 = FP,
  y01 = FN,
  y00 = TN,
  study = study,
  subgroup = generation
)
fit
summary(fit)

Fit the Reitsma Subgroup TMB Model

Description

Fits the Reitsma bivariate random-effects model with a single categorical covariate for diagnostic test accuracy (DTA) meta-analysis using a binomial-normal likelihood via a custom TMB template, which may offer improved numerical robustness in difficult or near-boundary cases.

Usage

fitReitsmaSubgroupTMB(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  subgroup,
  constrain = NULL,
  sensspec_constrain = NULL,
  variances = c("common", "unequal"),
  conflevel = 0.95,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

subgroup

A single categorical study-level subgroup variable (column name).

constrain

Optional character string specifying a simplified covariance structure for the Reitsma model.

This can be useful for sparse data, small meta-analyses, or for reproducing simplified bivariate models described in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Allowed values are:

NULL

The standard unconstrained Reitsma model is fitted.

"sigma_AB"

The covariance between logit-sensitivity and logit-specificity random effects is fixed at zero. Random effects remain independent.

"sigma2_A"

The between-study variance of logit-sensitivity is fixed at zero. This also implies a zero covariance.

"sigma2_B"

The between-study variance of logit-specificity is fixed at zero. This also implies a zero covariance.

"all"

All random-effects variance and covariance parameters are fixed at zero, resulting in a fixed-effects model.

These random-effects simplifications are currently only available for variances="common".

sensspec_constrain

Optional character vector specifying restrictions on subgroup-specific logit-sensitivity and/or logit-specificity parameters.

This can be useful for testing whether subgroup differences are present in sensitivity, specificity, or both.

Allowed values are:

"sens"

Constrain all subgroup-specific logit-sensitivity parameters to be equal. Subgroup differences are therefore only allowed in logit-specificity.

"spec"

Constrain all subgroup-specific logit-specificity parameters to be equal. Subgroup differences are therefore only allowed in logit-sensitivity.

Both constraints may be specified simultaneously, e.g. sensspec_constrain = c("sens", "spec"), which forces all subgroup-specific sensitivity and specificity parameters to be equal across subgroups.

If NULL (default), separate sensitivity and specificity parameters are estimated for each subgroup.

variances

Whether the between-study random-effects variance-covariance matrix should be assumed to be "common" (default) or "unequal" across subgroups. If "common", a single between-study variance-covariance matrix is estimated and shared across all subgroups. If "unequal", subgroup-specific variance-covariance matrices are estimated.

conflevel

Confidence level for confidence intervals. Default is 0.95.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Value

A list of class "ReitsmaSubgroupTMB" with components:

  • data: the original data set with derived quantities

  • fit: Optimization result from nlminb.

  • sdreport: TMB standard report.

  • sdreport2: Summary of reported parameters.

  • vcov: variance-covariance matrix of reported parameters.

  • sensspec: sensitivity and specificity estimates.

  • LRDOR: Diagnostic odds ratios and likelihood ratios.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • subgroups: The subgroup levels used in the model fit.

  • constrain: Random effects parameters fixed at zero.

  • sensspec_constrain: Whether sensitivities/specificities are assumed common across subgroups.

  • variances: Variance structure used in the fitted model.

References

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitReitsmaSubgroupTMB(
  data = anticcp,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study,
  subgroup = generation
)
fit
summary(fit)

Fit the Reitsma TMB Model

Description

Fits the Reitsma bivariate random-effects model for diagnostic test accuracy (DTA) meta-analysis using a binomial-normal likelihood via a custom TMB template, which may offer improved numerical robustness in difficult or near-boundary cases.

Usage

fitReitsmaTMB(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  constrain = NULL,
  conflevel = 0.95,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

constrain

Optional character string specifying a simplified covariance structure for the Reitsma model.

This can be useful for sparse data, small meta-analyses, or for reproducing simplified bivariate models described in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Allowed values are:

NULL

The standard unconstrained Reitsma model is fitted.

"sigma_AB"

The covariance between logit-sensitivity and logit-specificity random effects is fixed at zero. Random effects remain independent.

"sigma2_A"

The between-study variance of logit-sensitivity is fixed at zero. This also implies a zero covariance.

"sigma2_B"

The between-study variance of logit-specificity is fixed at zero. This also implies a zero covariance.

"all"

All random-effects variance and covariance parameters are fixed at zero, resulting in a fixed-effects model.

conflevel

Confidence level for confidence intervals. Default is 0.95.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Value

A list of class "ReitsmaTMB" with components:

  • data: the original data set with derived quantities

  • fit: Optimization result from nlminb.

  • sdreport: TMB standard report.

  • sdreport2: Summary of reported parameters.

  • vcov: variance-covariance matrix of reported parameters.

  • sensspec: sensitivity and specificity estimates.

  • LRDOR: Diagnostic odds ratio and likelihood ratios.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • constrain: Random effects parameters fixed at zero.

References

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitReitsmaTMB(
  data = anticcp,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study
)
summary(fit)

Fit the Rutter and Gatsonis (HSROC) Model

Description

Fits the hierarchical summary receiver operating characteristic (HSROC) model as proposed by Rutter and Gatsonis for meta-analysis of diagnostic test accuracy (DTA) studies using Template Model Builder (TMB).

Usage

fitRutterGatsonis(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  conflevel = 0.95,
  constrain = NULL,
  spec = NULL,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

conflevel

Confidence level for confidence intervals. Default is 0.95.

constrain

Optional character vector specifying model parameters that should be fixed at zero during estimation.

This can be useful for sparse data, small meta-analyses, or for reproducing simplified HSROC models described in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Allowed values are:

"sigma2_alpha"

Fix the between-study variance of the HSROC accuracy random effect at zero.

"sigma2_theta"

Fix the between-study variance of the HSROC threshold random effect at zero.

"shape"

Fix the HSROC shape parameter (beta) at zero, resulting in a symmetric summary ROC curve.

Multiple constraints may be specified simultaneously, e.g. constrain = c("sigma2_alpha", "shape").

If NULL (default), the unconstrained HSROC model is fitted.

spec

Optional specificity value at which sensitivity is estimated. If NULL, the median observed specificity is used as a proxy.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Details

The function internally transforms the data into long format and fits the model via maximum likelihood using TMB. Random effects are included for study-specific accuracy and threshold parameters.

Reitsma parameterization is recovered from the fitted HSROC parameters.

The constrain argument allows simplified HSROC models to be fitted by fixing selected parameters at zero. These constrained models may improve numerical stability in sparse datasets and can be used to reproduce several simplified models presented in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Constraints are imposed using parameter mapping within Template Model Builder (TMB), so constrained parameters are excluded from numerical optimization and treated as fixed constants.

Value

An object of class "RutterGatsonis" containing:

data

Processed input data with derived quantities.

fit

Optimization result from nlminb.

sdreport

TMB standard report.

sdreport2

Summary of reported parameters.

sensspec

Estimated sensitivity at given specificity with confidence intervals.

Reitsma_recovered

Recovered parameters in the Reitsma parameterization.

constrain

Parameters fixed at zero.

Note

Requires a compiled TMB model named "RutterGatsonis".

References

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("RF")
fit <- fitRutterGatsonis(
  data = RF,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study
)
summary(fit)

Fit the Rutter and Gatsonis LCA Model

Description

Fits the Rutter and Gatsonis latent class model for diagnostic test accuracy (DTA), allowing for an imperfect reference standard under conditional independence.

Usage

fitRutterGatsonisLCA(
  data,
  y11,
  y10,
  y01,
  y00,
  study,
  conflevel = 0.95,
  constrain = NULL,
  spec = NULL,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

y11

Number testing positive with both index and reference tests (column name).

y10

Number testing positive with index test but negative with reference test (column name).

y01

Number testing negative with index test but positive with reference test (column name).

y00

Number testing negative with both index and reference tests (column name).

study

Study identifier (column name).

conflevel

Confidence level for confidence intervals. Default is 0.95.

constrain

Optional character vector specifying model parameters of the index test that should be fixed at zero during estimation.

Allowed values are:

"sigma2_alpha"

Fix the between-study variance of the HSROC accuracy random effect at zero.

"sigma2_theta"

Fix the between-study variance of the HSROC threshold random effect at zero.

"shape"

Fix the HSROC shape parameter (beta) at zero, resulting in a symmetric summary ROC curve.

Multiple constraints may be specified simultaneously, e.g. constrain = c("sigma2_alpha", "shape").

If NULL (default), the unconstrained HSROC LCA model is fitted.

spec

Optional specificity value at which sensitivity is estimated. If NULL, a specificity of 0.8 is used as a proxy.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Value

An object of class "RutterGatsonisLCA" containing:

data

Processed input data with derived quantities.

fit

Optimization result from nlminb.

sdreport

TMB standard report.

sdreport2

Summary of reported parameters.

sensspec

Estimated index test sensitivity at given specificity with confidence intervals.

prevref

Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

Reitsma_recovered

Recovered parameters in the Reitsma parameterization.

constrain

Parameters fixed at zero.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("anticcp")
fit <- fitRutterGatsonisLCA(
  data = anticcp,
  y11 = TP,
  y10 = FP,
  y01 = FN,
  y00 = TN,
  study = study
)
fit
summary(fit)

Fit the Rutter and Gatsonis Regression Model

Description

Fits a general HSROC meta-regression model using user-supplied design matrices for estimation and prediction.

Usage

fitRutterGatsonisReg(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  Z,
  Z_pred = NULL,
  map = NULL,
  init = NULL,
  spec = NULL,
  conflevel = 0.95,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

Z

Design matrix containing covariate values for model fitting. The current implementation is intended primarily for study-level covariates. In the long-format representation, this typically means that each study is represented by two consecutive rows with identical covariate values. The number of rows of Z must equal twice the number of studies.

Z_pred

Prediction design matrix used to obtain covariate-specific parameter estimates and SROC curves. Each row defines a covariate pattern at which predictions are evaluated. The number of columns of Z_pred must equal the number of columns of Z. If NULL (default), a single row of zeros is used. For meaningful predictions, users will typically want to specify Z_pred explicitly.

map

Optional named list of parameter mappings passed to MakeADFun.

Parameter mapping allows selected model parameters to be fixed or constrained during estimation. This can be useful for fitting simplified HSROC models, imposing equality constraints, or reproducing model specifications described in the literature.

Each component of map should be a factor vector with the same length as the corresponding parameter. Parameters assigned NA levels are fixed at their initial values supplied via the init argument, whereas parameters sharing the same factor level are estimated as equal.

This is an advanced feature intended primarily for users familiar with Template Model Builder (TMB).

If NULL (default), all model parameters are estimated freely.

Example map = list(shape_coef=factor(c(1, rep(NA, ncol(Z) - 1)))).

init

Optional list of initial parameter values. If NULL (default), all fixed and random effects are initialized to zero. Advanced users may provide a named list containing:

accuracy_coef

Initial values for the accuracy regression coefficients.

threshold_coef

Initial values for the threshold regression coefficients.

shape_coef

Initial values for the shape regression coefficients.

log_sigma_alpha

Initial value for the log standard deviation of the accuracy random effects.

log_sigma_theta

Initial value for the log standard deviation of the threshold random effects.

alpha

Initial values for the study-specific accuracy random effects.

theta

Initial values for the study-specific threshold random effects.

The lengths of accuracy_coef, threshold_coef, and shape_coef must equal the number of columns in Z. The lengths of alpha and theta must equal the number of studies.

spec

Optional specificity value or vector of specificity values at which sensitivity is evaluated for each covariate pattern specified in Z_pred. If NULL, the median observed specificity is used.

conflevel

Confidence level for confidence intervals. Default is 0.95.

verbose

Logical indicating whether TMB optimization output should be printed (default: FALSE).

Details

This function is intended for advanced users who wish to specify design matrices directly. The user is responsible for constructing appropriate design matrices, choosing prediction covariate patterns through Z_pred, and interpreting or visualizing the resulting regression model.

By default, all fixed and random effects are initialized at zero. For difficult optimization problems, user-supplied starting values may be provided through the init argument.

The fitted model estimates covariate effects on the HSROC accuracy, threshold, and optionally shape parameters. Predicted sensitivities are obtained by evaluating the resulting SROC curve(s) at the specificity value(s) supplied through spec and the covariate patterns defined by Z_pred.

Value

An object of class "RutterGatsonisReg" containing:

data

Processed input data with derived quantities.

fit

Optimization result returned by nlminb.

sdreport

TMB standard report object.

sdreport2

Summary of reported model parameters and derived quantities.

sensspec

Estimated sensitivities at the specified specificity value(s), including confidence intervals.

Note

Requires a compiled TMB model named "RutterGatsonisReg".

References

Reitsma, J. B., Glas, A. S., Rutjes, A. W. S., Scholten, R. J. P. M., Bossuyt, P. M., & Zwinderman, A. H. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("RF")
RF2        <- RF[RF$method %in% c("LA","ELISA","Nephelometry"),]
RF2$method <- factor(RF2$method,levels=c("LA","ELISA","Nephelometry"))
Z <- model.matrix(~ method, data = RF2)
Z <- Z[rep(seq_len(nrow(Z)), each = 2), , drop = FALSE]
Z_pred <- matrix(c(1,0,0,1,1,0,1,0,1),ncol=3,nrow=3,byrow=TRUE)

fit <- fitRutterGatsonisReg(
  data = RF2,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study,
  Z = Z,
  Z_pred = Z_pred
)

summary(fit)

Fit the Rutter and Gatsonis Subgroup Model

Description

The function fits an HSROC model with a single categorical study-level covariate (subgroup).

Usage

fitRutterGatsonisSubgroup(
  data,
  TP,
  FP,
  FN,
  TN,
  study,
  subgroup,
  constrain = NULL,
  spec = NULL,
  conflevel = 0.95,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

study

Study identifier (column name).

subgroup

A single categorical study-level subgroup variable (column name).

constrain

Optional character vector specifying model parameters that should be constrained during estimation.

This can be useful for sparse data, small meta-analyses, or for reproducing simplified HSROC models described in the Cochrane Handbook for Diagnostic Test Accuracy Reviews.

Allowed values are:

"sigma2_alpha"

Fix the between-study variance of the HSROC accuracy random effect at zero.

"sigma2_theta"

Fix the between-study variance of the HSROC threshold random effect at zero.

"accuracy"

No subgroup effect on accuracy.

"threshold"

No subgroup effect on threshold.

"shape"

No subgroup effect on shape.

"shape_zero"

All shape parameters (beta's) are fixed at zero.

Multiple constraints may be specified simultaneously, e.g. constrain = c("sigma2_alpha", "shape").

shape_zero overrides shape.

If NULL (default), the unconstrained HSROC model is fitted.

spec

Optional specificity value or vector of specificity values at which sensitivity is estimated. If NULL, the median observed specificity is used as a proxy.

conflevel

Confidence level for confidence intervals. Default is 0.95.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Details

The function fits an HSROC model with a single categorical study-level covariate (subgroup). Separate subgroup effects are estimated for the accuracy and threshold parameters. Optionally, subgroup-specific effects can also be estimated for the shape parameter.

The fitted model returns subgroup-specific summary sensitivity estimates evaluated at user-specified specificity values. If spec = NULL, the median observed specificity is used as a proxy.

This function is intended as a convenient wrapper for subgroup analyses with a single categorical covariate and provides output suitable for dedicated summary(), plot(), and forest() methods.

Value

An object of class "RutterGatsonisSubgroup" containing:

data

Processed input data with derived quantities.

fit

Optimization result from nlminb.

sdreport

TMB standard report.

sdreport2

Summary of reported subgroup-specific parameters.

sensspec

Estimated subgroup-specific sensitivities at the given specificity value(s), with confidence intervals.

constrain

Constraints on parameters applied during model fitting.

subgroups

The subgroup levels used in the model fit.

Note

Requires a compiled TMB model named "RutterGatsonisReg".

References

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("RF")
fit <- fitRutterGatsonisSubgroup(
  data = RF,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  study = study,
  subgroup = method
)
summary(fit)

Fit the Rutter and Gatsonis Subgroup LCA Model

Description

The function fits an HSROC model with a single categorical study-level covariate (subgroup), allowing for an imperfect reference standard assuming conditional independence.

Usage

fitRutterGatsonisSubgroupLCA(
  data,
  y11,
  y10,
  y01,
  y00,
  study,
  subgroup,
  constrain = NULL,
  prev_variances = c("common", "unequal"),
  spec = NULL,
  conflevel = 0.95,
  verbose = FALSE
)

Arguments

data

A data.frame containing study-level data.

y11

Number testing positive with both index and reference tests (column name).

y10

Number testing positive with index test but negative with reference test (column name).

y01

Number testing negative with index test but positive with reference test (column name).

y00

Number testing negative with both index and reference tests (column name).

study

Study identifier (column name).

subgroup

A single categorical study-level subgroup variable (column name).

constrain

Optional character vector specifying model parameters that should be constrained during estimation.

Allowed values are:

"sigma2_alpha"

Fix the between-study variance of the HSROC accuracy random effect at zero.

"sigma2_theta"

Fix the between-study variance of the HSROC threshold random effect at zero.

"accuracy"

No subgroup effect on accuracy.

"threshold"

No subgroup effect on threshold.

"shape"

No subgroup effect on shape.

"shape_zero"

All shape parameters (beta's) are fixed at zero.

Multiple constraints may be specified simultaneously, e.g. constrain = c("sigma2_alpha", "shape").

shape_zero overrides shape.

If NULL (default), the unconstrained HSROC model is fitted.

prev_variances

Whether the between-study random-effects variance for logit prevalence should be assumed to be "common" (default) or "unequal" across subgroups. If "common", a single between-study variance is estimated and shared across all subgroups. If "unequal", subgroup-specific variances are estimated.

spec

Optional specificity value at which sensitivity is estimated. If NULL, a specificity of 0.8 is used as a proxy.

conflevel

Confidence level for confidence intervals. Default is 0.95.

verbose

Whether TMB optimization output should be printed (default: FALSE).

Value

An object of class "RutterGatsonisSubgroupLCA" containing:

data

Processed input data with derived quantities.

fit

Optimization result from nlminb.

sdreport

TMB standard report.

sdreport2

Summary of reported subgroup-specific parameters.

sensspec

Estimated subgroup-specific index test sensitivities at the given specificity value(s), with confidence intervals.

prevref

Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

constrain

Constraints on parameters applied during model fitting.

subgroups

The subgroup levels used in the model fit.

prev_variances

Prevalence variance structure used in the fitted model.

Note

Requires a compiled TMB model named "RutterGatsonisSubgroupLCA".

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Reitsma, J. B., et al. (2005). Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. Journal of Clinical Epidemiology, 58(10), 982–990. doi:10.1016/j.jclinepi.2005.02.022

Rutter, C. M., & Gatsonis, C. A. (2001). A hierarchical regression approach to meta-analysis of diagnostic test accuracy evaluations. Statistics in Medicine, 20(19), 2865–2884. doi:10.1002/sim.942

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Examples

data("schuetz")
fit <- fitRutterGatsonisSubgroupLCA(
  data = schuetz,
  y11 = TP,
  y10 = FP,
  y01 = FN,
  y00 = TN,
  study = study,
  subgroup = test
)
fit
summary(fit)

Coupled Forest Plot

Description

Produces coupled forest plots.

Usage

forest(x, ...)

Arguments

x

Object

...

Additional arguments

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Diagnostic Test Accuracy Meta-Analysis

Description

Provides coupled forest plots of sensitivities and specificities with Clopper-Pearson confidence limits.

Usage

## S3 method for class 'HoyerAFT'
forest(x, conflevel = 0.95, ...)

Arguments

x

Object of class "HoyerAFT"

conflevel

Confidence level for confidence intervals. Default is 0.95.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Diagnostic Test Accuracy Meta-Analysis

Description

Provides coupled forest plots of sensitivities and specificities with Clopper-Pearson confidence limits.

Usage

## S3 method for class 'Reitsma'
forest(x, conflevel = 0.95, ...)

Arguments

x

Object of class "Reitsma"

conflevel

Confidence level for confidence intervals. Default is 0.95.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Latent Class Diagnostic Test Accuracy Meta-Analysis

Description

Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model. Confidence intervals are based on the conditional posterior variance of the study-specific random effects obtained from the TMB Laplace approximation.

Usage

## S3 method for class 'ReitsmaLCA'
forest(x, conflevel = 0.95, ...)

Arguments

x

Object of class "ReitsmaLCA"

conflevel

Confidence level for confidence intervals. Default is 0.95.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Diagnostic Test Accuracy Meta-Analysis

Description

Provides coupled forest plots of sensitivities and specificities with Clopper-Pearson confidence limits.

Usage

## S3 method for class 'ReitsmaSubgroup'
forest(
  x,
  conflevel = 0.95,
  subgroup_label = "Subgroup",
  order = c("study", "subgroup"),
  ...
)

Arguments

x

Object of class "ReitsmaSubgroup"

conflevel

Confidence level for confidence intervals. Default is 0.95.

subgroup_label

Column name for the subgroup. Defaults to "Subgroup".

order

Specifies the ordering of studies in the forest plot. Can be "study" (default), which orders observations by study identifier and then subgroup, or "subgroup", which orders observations by subgroup and then study identifier.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Latent Class Diagnostic Test Accuracy Meta-Analysis

Description

Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model. Confidence intervals are based on the conditional posterior variance of the study-specific random effects obtained from the TMB Laplace approximation.

Usage

## S3 method for class 'ReitsmaSubgroupLCA'
forest(
  x,
  conflevel = 0.95,
  subgroup_label = "Subgroup",
  order = c("study", "subgroup"),
  ...
)

Arguments

x

Object of class "ReitsmaSubgroupLCA"

conflevel

Confidence level for confidence intervals. Default is 0.95.

subgroup_label

Column name for the subgroup. Defaults to "Subgroup".

order

Specifies the ordering of studies in the forest plot. Can be "study" (default), which orders observations by study identifier and then subgroup, or "subgroup", which orders observations by subgroup and then study identifier.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Diagnostic Test Accuracy Meta-Analysis

Description

Provides coupled forest plots of sensitivities and specificities with Clopper-Pearson confidence limits.

Usage

## S3 method for class 'ReitsmaSubgroupTMB'
forest(
  x,
  conflevel = 0.95,
  subgroup_label = "Subgroup",
  order = c("study", "subgroup"),
  ...
)

Arguments

x

Object of class "ReitsmaSubgroupTMB"

conflevel

Confidence level for confidence intervals. Default is 0.95.

subgroup_label

Column name for the subgroup. Defaults to "Subgroup".

order

Specifies the ordering of studies in the forest plot. Can be "study" (default), which orders observations by study identifier and then subgroup, or "subgroup", which orders observations by subgroup and then study identifier.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Diagnostic Test Accuracy Meta-Analysis

Description

Provides coupled forest plots of sensitivities and specificities with Clopper-Pearson confidence limits.

Usage

## S3 method for class 'RutterGatsonis'
forest(x, conflevel = 0.95, ...)

Arguments

x

Object of class "RutterGatsonis"

conflevel

Confidence level for confidence intervals. Default is 0.95.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Latent Class Diagnostic Test Accuracy Meta-Analysis

Description

Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model. Confidence intervals are based on the conditional posterior variance of the study-specific random effects obtained from the TMB Laplace approximation.

Usage

## S3 method for class 'RutterGatsonisLCA'
forest(x, conflevel = 0.95, ...)

Arguments

x

Object of class "RutterGatsonisLCA"

conflevel

Confidence level for confidence intervals. Default is 0.95.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Diagnostic Test Accuracy Meta-Analysis

Description

Provides coupled forest plots of sensitivities and specificities with Clopper-Pearson confidence limits.

Usage

## S3 method for class 'RutterGatsonisSubgroup'
forest(
  x,
  conflevel = 0.95,
  subgroup_label = "Subgroup",
  order = c("study", "subgroup"),
  ...
)

Arguments

x

Object of class "RutterGatsonisSubgroup"

conflevel

Confidence level for confidence intervals. Default is 0.95.

subgroup_label

Column name for the subgroup. Defaults to "Subgroup".

order

Specifies the ordering of studies in the forest plot. Can be "study" (default), which orders observations by study identifier and then subgroup, or "subgroup", which orders observations by subgroup and then study identifier.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Coupled Forest Plot for Latent Class Diagnostic Test Accuracy Meta-Analysis

Description

Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model. Confidence intervals are based on the conditional posterior variance of the study-specific random effects obtained from the TMB Laplace approximation.

Usage

## S3 method for class 'RutterGatsonisSubgroupLCA'
forest(
  x,
  conflevel = 0.95,
  subgroup_label = "Subgroup",
  order = c("study", "subgroup"),
  ...
)

Arguments

x

Object of class "RutterGatsonisSubgroupLCA"

conflevel

Confidence level for confidence intervals. Default is 0.95.

subgroup_label

Column name for the subgroup. Defaults to "Subgroup".

order

Specifies the ordering of studies in the forest plot. Can be "study" (default), which orders observations by study identifier and then subgroup, or "subgroup", which orders observations by subgroup and then study identifier.

...

Additional graphical arguments (not currently in use)

Value

Invisibly returns a forestploter object. Users may further modify the plot using forestploter functions before printing or exporting.


Compute Initial Parameter Values for HoyerAFT Models

Description

Computes initial values for the threshold-based bivariate time-to-event model of Hoyer et al. (2018).

Usage

initHoyerAFT(restructured, dist = "loglogistic")

Arguments

restructured

A data frame in interval format as produced by restructure_data (specifically the restructured component of its output). Must contain the columns:

study

Study identifier

lowerB

Lower interval bound

upperB

Upper interval bound

events0

Non-diseased counts within interval

events1

Diseased counts within interval

ctype

Censoring type (1 = left, 2 = interval, 3 = right)

lcutmean

Midpoint of log-threshold interval

dist

Character string specifying the parametric distribution used in the survival regression models. Must be one of: "weibull", "lognormal", or "loglogistic". Default is "loglogistic".

Details

The function fits separate intercept-only parametric survival models for diseased and non-diseased groups using weighted interval-censored likelihoods. It further derives initial estimates of between-study variability based on study-specific weighted averages of log-thresholds.

To ensure compatibility with survival::survreg, interval bounds are modified as follows:

  • Left-censored intervals (ctype = 1) are assigned a small positive lower bound.

  • Right-censored intervals (ctype = 3) are assigned an infinite upper bound.

Value

A single-row data frame containing initial parameter values:

beta0_init

Intercept for non-diseased group

lambda0_init

Scale parameter for non-diseased group

beta1_init

Intercept for diseased group

lambda1_init

Scale parameter for diseased group

su0_init

Standard deviation of random effects (non-diseased)

su1_init

Standard deviation of random effects (diseased)

coru0u1_init

Correlation between random effects

distcode

Numeric code for the distribution (1 = Weibull, 2 = lognormal, 3 = loglogistic)

References

Hoyer, A., Hirt, S., Kuss, O. (2018). Meta-analysis of full ROC curves using bivariate time-to-event models for interval-censored data. Research Synthesis Methods, 9(1), 62-72. doi:10.1002/jrsm.1273

Examples

data("diabetes")
res <- restructure_data(
  data = diabetes,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  threshold = threshold,
  study = study,
  smallest = 2,
  largest = 10
)
init <- initHoyerAFT(res$restructured)

Extract Log-Likelihood from Diagnostic Test Accuracy Models

Description

Returns the maximized log-likelihood for a fitted diagnostic test accuracy meta-analysis model. The returned value is an object of class "logLik" and includes the number of estimated parameters (df) and the number of observations used in model fitting (nobs).

Usage

## S3 method for class 'DTAmodel'
logLik(object, ...)

## S3 method for class 'HoyerAFT'
logLik(object, ...)

## S3 method for class 'Reitsma'
logLik(object, ...)

## S3 method for class 'ReitsmaSubgroup'
logLik(object, ...)

## S3 method for class 'ReitsmaLCA'
logLik(object, ...)

## S3 method for class 'ReitsmaSubgroupLCA'
logLik(object, ...)

## S3 method for class 'ReitsmaSubgroupTMB'
logLik(object, ...)

## S3 method for class 'ReitsmaTMB'
logLik(object, ...)

Arguments

object

A fitted model object.

...

Not used.

Value

An object of class "logLik".

See Also

anova.dtametaTMB()


Pap Dataset

Description

This is the pap dataset from Fahey et al. (1995) from a meta-analysis comparing Papanicolaou (Pap) test results with histology for the diagnosis of cervical cancer.

Usage

pap

Format

A data frame with 59 rows and 6 variables:

id

Study identifier

type

Test taken during screening (SC) or follow-up (FU)

y11

Number testing positive with both tests

y10

Number testing positive with index test but negative with reference test

y01

Number testing negative with index test but positive with reference test

y00

Number testing negative with both tests

Note

The data set was reconstructed from the SAS code in the supplementary material from Liu et al. (2015).

Source

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Fahey, M., Irwig, L., & Macaskill, P. (1995). Meta-analysis of pap test accuracy. American Journal of Epidemiology, 141(7), 680-689. doi:10.1093/oxfordjournals.aje.a117485


Plot Results from a HoyerAFT Model

Description

Produces a hierarchical summary receiver operating characteristic (HSROC) plot from a fitted HoyerAFT model. The plot shows study-level sensitivity and specificity estimates together with the meta-analytic HSROC curve derived from the fitted model.

Usage

## S3 method for class 'HoyerAFT'
plot(
  x,
  symbol = c("rectangle", "ellipse", "diamond", "triangle", "cross", "plus", "star"),
  scale = 0.02,
  size = c("equal", "sampsize", "se", "sampsize_revman", "se_revman"),
  HSROC = TRUE,
  thresholdrange = NULL,
  main = "Diagnostic Test Accuracy Meta-Analysis",
  studyCI = FALSE,
  conflevel = 0.95,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "HoyerAFT" as returned by fitHoyerAFT. Must contain:

data

Original processed data including sensitivity (sens) and false positive rate (fpr)

sdreport2

Summary of model parameters

distcode

Distribution code (1 = Weibull, 2 = lognormal, 3 = loglogistic)

symbol

Character string specifying the symbol used for study-level estimates. One of "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". The default is "rectangle".

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"equal"

All studies shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

HSROC

if TRUE, the HSROC curve is added to the plot. Default is TRUE.

thresholdrange

A numeric vector of length 2 giving the range of threshold over which sensitivities and specificities are predicted. If NULL (default), then the minimum and maximum thresholds from the data are used.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

conflevel

Confidence level for the study-level confidence intervals. Default is 0.95.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments (currently unused).

Details

The plot includes:

  • Study-specific sensitivity and false positive rate estimates

  • Symbols representing study observations, with dimensions determined by the selected graphical sizing method.

  • Lines connecting thresholds within studies

  • A meta-analytic HSROC curve based on the fitted AFT model

The HSROC curve is constructed using the estimated model parameters and depends on the specified distribution:

  • Weibull

  • Lognormal

  • Loglogistic

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Value

No return value. Called for its side effect of producing a plot.

See Also

fitHoyerAFT fitHoyer


Plot Results from a Reitsma Model

Description

Produces a summary ROC plot for objects of class "Reitsma" obtained from fitReitsma. The plot displays study-level estimates of sensitivity and specificity, the summary operating point, and corresponding confidence and prediction regions. Optionally, the HSROC (hierarchical summary ROC) curve can be overlaid.

Usage

## S3 method for class 'Reitsma'
plot(
  x,
  symbol = c("rectangle", "ellipse", "diamond", "triangle", "cross", "plus", "star"),
  scale = 0.02,
  size = c("fisher", "fisher_revman", "equal", "sampsize", "se", "sampsize_revman",
    "se_revman"),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = FALSE,
  specrange = c(0.7, 0.995),
  conflevel = 0.95,
  predlevel = 0.95,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "Reitsma", as returned by fitReitsma.

symbol

Character string specifying the symbol used for study-level estimates. One of "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". The default is "rectangle".

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"fisher"

Size proportional to a decomposition of Fisher's Information matrix. Default.

"fisher_revman"

Horizontal and vertical symbol dimensions are based on the same per-study percentage contributions to the logit sensitivity and logit specificity Fisher information as size = "fisher". These percentages are then converted to graphical dimensions using the same RevMan-style normalization applied under "sampsize_revman" and "se_revman".

"equal"

All studies shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

if TRUE, the HSROC curve is added to the plot. Default is FALSE.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

conflevel

Confidence level for the confidence region. Default is 0.95.

predlevel

Confidence level for the prediction region. Default is 0.95.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown using the selected symbol (rectangles by default), where the size reflects approximate study weights derived from the Fisher information matrix (default).

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • Summary (pooled) estimate

  • confidence region around the summary point

  • prediction region reflecting between-study variability

  • Optional HSROC curve (if HSROC = TRUE)

Confidence and prediction regions are derived using the delta method based on the estimated variance-covariance structure of the model.

Value

No return value. Called for its side effect of producing a plot.

References

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Riley, R. D., Ensor, J., Jackson, D., & Burke, D. L. (2018). Deriving percentage study weights in multi-parameter meta-analysis models: with application to meta-regression, network meta-analysis and one-stage individual participant data models. Statistical Methods in Medical Research, 27(10), 2885–2905. doi:10.1177/0962280216688033

See Also

fitReitsma


Plot Results from a Reitsma LCA Model

Description

Produces a summary ROC plot for objects of class "ReitsmaLCA" obtained from fitReitsmaLCA. Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model.

Usage

## S3 method for class 'ReitsmaLCA'
plot(
  x,
  symbol = c("rectangle", "ellipse", "diamond", "triangle", "cross", "plus", "star"),
  scale = 0.02,
  size = c("eb", "equal", "sampsize", "eb_revman", "sampsize_revman"),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = FALSE,
  specrange = c(0.7, 0.995),
  conflevel = 0.95,
  predlevel = 0.95,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "ReitsmaLCA", as returned by fitReitsmaLCA.

symbol

Character string specifying the symbol used for study-level estimates. One of "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". The default is "rectangle".

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"eb"

Horizontal and vertical symbol dimensions are proportional to normalized inverse posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates, respectively.

"equal"

All studies are shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are both proportional to relative total study sample size. The same dimension measure is used horizontally and vertically because true disease status is latent.

"eb_revman"

RevMan-style graphical scaling applied to the inverse conditional posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension. This is an analogous graphical extension for latent-class models and is not an original Cochrane latent-class weighting method.

"sampsize_revman"

RevMan-style graphical scaling based on total study sample size. The same transformed total-sample-size measure is used horizontally and vertically.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

if TRUE, the HSROC curve is added to the plot. Default is FALSE.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

conflevel

Confidence level for the confidence region. Default is 0.95.

predlevel

Confidence level for the prediction region. Default is 0.95.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown using the selected symbol (rectangles by default).

The following elements are displayed:

  • Study-level sensitivity and specificity estimates (Empirical Bayes Estimates)

  • Summary (pooled) estimate

  • confidence region around the summary point

  • prediction region reflecting between-study variability

  • Optional HSROC curve (if HSROC = TRUE)

Confidence and prediction regions are derived using the delta method based on the estimated variance-covariance structure of the model.

Value

No return value. Called for its side effect of producing a plot.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

See Also

fitReitsmaLCA


Plot Results from a Reitsma Subgroup Model

Description

Produces a summary ROC plot for objects of class "ReitsmaSubgroup" obtained from fitReitsmaSubgroup. The plot displays study-level estimates of sensitivity and specificity, the summary operating point, and corresponding confidence and prediction regions. Optionally, the HSROC (hierarchical summary ROC) curve can be overlaid.

Usage

## S3 method for class 'ReitsmaSubgroup'
plot(
  x,
  symbol = NULL,
  scale = 0.02,
  size = c("equal", "fisher", "fisher_revman", "sampsize", "se", "sampsize_revman",
    "se_revman"),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  col = NULL,
  nudge_legend = -0.4,
  HSROC = FALSE,
  specrange = c(0.7, 0.995),
  conflevel = 0.95,
  predlevel = 0.95,
  connectstudies = FALSE,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "ReitsmaSubgroup", as returned by fitReitsmaSubgroup.

symbol

Character vector specifying the symbols used for study-level estimates of the subgroups. One can choose "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". If NULL, symbols are generated automatically.

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"fisher"

Study-symbol dimensions represent percentage contributions to the estimated logit sensitivity and logit specificity of the study’s own subgroup. Weights sum to 100 separately within each subgroup and outcome dimension. If sensspec_constrain is used in fitReitsmaSubgroup to constrain logit sensitivity and/or logit specificity to a common value across subgroups, weights for the constrained outcome dimension(s) instead sum to 100 across all studies and subgroups combined, reflecting that all studies then inform a single shared parameter.

"fisher_revman"

Horizontal and vertical symbol dimensions are based on the same per-study percentage contributions to the logit sensitivity and logit specificity Fisher information as size = "fisher". These percentages are then converted to graphical dimensions using the same RevMan-style normalization applied under "sampsize_revman" and "se_revman".

"equal"

All studies shown with equal size. Default.

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

col

Vector of colours used for subgroup-specific HSROC curves, study-level point estimates, summary points, confidence and prediction region. If NULL, colours are generated automatically.

nudge_legend

Numeric horizontal offset for the subgroup legend. More negative values move the legend further right, outside the plotting area. Values closer to zero move it closer to the panel. Default is -0.4.

HSROC

if TRUE, the HSROC curve is added to the plot. Default is FALSE.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

conflevel

Confidence level for the confidence region. Default is 0.95.

predlevel

Confidence level for the prediction region. Default is 0.95.

connectstudies

Whether the point estimates of two subgroups within the same study should be connected. Defaults to FALSE.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown with subgroup-specific symbols and colours.

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • Summary (pooled) estimate

  • confidence region around the summary point

  • prediction region reflecting between-study variability

  • Optional HSROC curve (if HSROC = TRUE)

Confidence and prediction regions are derived using the delta method based on the estimated variance-covariance structure of the model.

Value

No return value. Called for its side effect of producing a plot.

References

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

Riley, R. D., Ensor, J., Jackson, D., & Burke, D. L. (2018). Deriving percentage study weights in multi-parameter meta-analysis models: with application to meta-regression, network meta-analysis and one-stage individual participant data models. Statistical Methods in Medical Research, 27(10), 2885–2905. doi:10.1177/0962280216688033

See Also

fitReitsmaSubgroup


Plot Results from a Reitsma Subgroup LCA Model

Description

Produces a summary ROC plot for objects of class "ReitsmaSubgroupLCA" obtained from fitReitsmaSubgroupLCA. Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model.

Usage

## S3 method for class 'ReitsmaSubgroupLCA'
plot(
  x,
  symbol = NULL,
  scale = 0.02,
  size = c("eb", "equal", "sampsize", "eb_revman", "sampsize_revman"),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  col = NULL,
  nudge_legend = -0.4,
  HSROC = FALSE,
  specrange = c(0.7, 0.995),
  conflevel = 0.95,
  predlevel = 0.95,
  connectstudies = FALSE,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "ReitsmaSubgroupLCA", as returned by fitReitsmaSubgroupLCA.

symbol

Character vector specifying the symbols used for study-level estimates of the subgroups. One can choose "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". If NULL, symbols are generated automatically.

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"eb"

Horizontal and vertical symbol dimensions are proportional to normalized inverse posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates, respectively.

"equal"

All studies are shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are both proportional to relative total study sample size. The same dimension measure is used horizontally and vertically because true disease status is latent.

"eb_revman"

RevMan-style graphical scaling applied to the inverse conditional posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension. This is an analogous graphical extension for latent-class models and is not an original Cochrane latent-class weighting method.

"sampsize_revman"

RevMan-style graphical scaling based on total study sample size. The same transformed total-sample-size measure is used horizontally and vertically.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

col

Vector of colours used for subgroup-specific HSROC curves, study-level point estimates, summary points, confidence and prediction region. If NULL, colours are generated automatically.

nudge_legend

Numeric horizontal offset for the subgroup legend. More negative values move the legend further right, outside the plotting area. Values closer to zero move it closer to the panel. Default is -0.4.

HSROC

if TRUE, the HSROC curve is added to the plot. Default is FALSE.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

conflevel

Confidence level for the confidence region. Default is 0.95.

predlevel

Confidence level for the prediction region. Default is 0.95.

connectstudies

Whether the point estimates of two subgroups within the same study should be connected. Defaults to FALSE.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown with subgroup-specific symbols and colours.

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • Summary (pooled) estimate

  • confidence region around the summary point

  • prediction region reflecting between-study variability

  • Optional HSROC curve (if HSROC = TRUE)

Confidence and prediction regions are derived using the delta method based on the estimated variance-covariance structure of the model.

Value

No return value. Called for its side effect of producing a plot.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

See Also

fitReitsmaSubgroupLCA


Plot Results from a Reitsma Subgroup TMB Model

Description

Produces a summary ROC plot for objects of class "ReitsmaSubgroupTMB" obtained from fitReitsmaSubgroupTMB. The plot displays study-level estimates of sensitivity and specificity, the summary operating point, and corresponding confidence and prediction regions. Optionally, the HSROC (hierarchical summary ROC) curve can be overlaid.

Usage

## S3 method for class 'ReitsmaSubgroupTMB'
plot(
  x,
  symbol = NULL,
  scale = 0.02,
  size = c("equal", "fisher", "fisher_revman", "sampsize", "se", "sampsize_revman",
    "se_revman"),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  col = NULL,
  nudge_legend = -0.4,
  HSROC = FALSE,
  specrange = c(0.7, 0.995),
  conflevel = 0.95,
  predlevel = 0.95,
  connectstudies = FALSE,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "ReitsmaSubgroupTMB", as returned by fitReitsmaSubgroupTMB.

symbol

Character vector specifying the symbols used for study-level estimates of the subgroups. One can choose "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". If NULL, symbols are generated automatically.

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"fisher"

Study-symbol dimensions represent percentage contributions to the estimated logit sensitivity and logit specificity of the study’s own subgroup. Weights sum to 100 separately within each subgroup and outcome dimension. If sensspec_constrain is used in fitReitsmaSubgroupTMB to constrain logit sensitivity and/or logit specificity to a common value across subgroups, weights for the constrained outcome dimension(s) instead sum to 100 across all studies and subgroups combined, reflecting that all studies then inform a single shared parameter.

"fisher_revman"

Horizontal and vertical symbol dimensions are based on the same per-study percentage contributions to the logit sensitivity and logit specificity Fisher information as size = "fisher". These percentages are then converted to graphical dimensions using the same RevMan-style normalization applied under "sampsize_revman" and "se_revman".

"equal"

All studies shown with equal size. Default.

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

col

Vector of colours used for subgroup-specific HSROC curves, study-level symbols, summary points, confidence and prediction region. If NULL, colours are generated automatically.

nudge_legend

Numeric horizontal offset for the subgroup legend. More negative values move the legend further right, outside the plotting area. Values closer to zero move it closer to the panel. Default is -0.4.

HSROC

if TRUE, the HSROC curve is added to the plot. Default is FALSE.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

conflevel

Confidence level for the confidence region. Default is 0.95.

predlevel

Confidence level for the prediction region. Default is 0.95.

connectstudies

Whether the point estimates of two subgroups within the same study should be connected. Defaults to FALSE.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown with study-specific symbols and colours.

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • Summary (pooled) estimate

  • confidence region around the summary point

  • prediction region reflecting between-study variability

  • Optional HSROC curve (if HSROC = TRUE)

Confidence and prediction regions are derived using the delta method based on the estimated variance-covariance structure of the model.

Value

No return value. Called for its side effect of producing a plot.

References

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

See Also

fitReitsmaSubgroupTMB


Plot Results from a ReitsmaTMB Model

Description

Produces a summary ROC plot for objects of class "ReitsmaTMB" obtained from fitReitsmaTMB. The plot displays study-level estimates of sensitivity and specificity, the summary operating point, and corresponding confidence and prediction regions. Optionally, the HSROC (hierarchical summary ROC) curve can be overlaid.

Usage

## S3 method for class 'ReitsmaTMB'
plot(
  x,
  symbol = c("rectangle", "ellipse", "diamond", "triangle", "cross", "plus", "star"),
  scale = 0.02,
  size = c("fisher", "fisher_revman", "equal", "sampsize", "se", "sampsize_revman",
    "se_revman"),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = FALSE,
  specrange = c(0.7, 0.995),
  conflevel = 0.95,
  predlevel = 0.95,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "ReitsmaTMB", as returned by fitReitsmaTMB.

symbol

Character string specifying the symbol used for study-level estimates. One of "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". The default is "rectangle".

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"fisher"

Size proportional to a decomposition of Fisher's Information matrix. Default.

"fisher_revman"

Horizontal and vertical symbol dimensions are based on the same per-study percentage contributions to the logit sensitivity and logit specificity Fisher information as size = "fisher". These percentages are then converted to graphical dimensions using the same RevMan-style normalization applied under "sampsize_revman" and "se_revman".

"equal"

All studies shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

If TRUE, the HSROC curve is added to the plot. Default is FALSE.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

conflevel

Confidence level for the confidence region. Default is 0.95.

predlevel

Confidence level for the prediction region. Default is 0.95.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown using the selected symbol (rectangles by default).

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • Summary (pooled) estimate

  • confidence region around the summary point

  • prediction region reflecting between-study variability

  • Optional HSROC curve (if HSROC = TRUE)

Confidence and prediction regions are derived using the delta method based on the estimated variance-covariance structure of the model.

Value

No return value. Called for its side effect of producing a plot.

References

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

See Also

fitReitsmaTMB


Plot Results from a Rutter and Gatsonis Model

Description

Produces a summary ROC plot for objects of class "RutterGatsonis" obtained from fitRutterGatsonis. The plot displays study-level estimates of sensitivity and specificity and the HSROC (hierarchical summary ROC).

Usage

## S3 method for class 'RutterGatsonis'
plot(
  x,
  symbol = c("rectangle", "ellipse", "diamond", "triangle", "cross", "plus", "star"),
  scale = 0.02,
  size = c("fisher", "fisher_revman", "equal", "sampsize", "se", "sampsize_revman",
    "se_revman"),
  specrange = c(0.7, 0.995),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = TRUE,
  conflevel = 0.95,
  studyCI = FALSE,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "RutterGatsonis", as returned by fitRutterGatsonis.

symbol

Character string specifying the symbol used for study-level estimates. One of "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". The default is "rectangle".

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"fisher"

Size proportional to a decomposition of Fisher's Information matrix with respect to the recovered pooled logit sensitivity and specificity. Default.

"fisher_revman"

Horizontal and vertical symbol dimensions are based on the same per-study percentage contributions to the logit sensitivity and logit specificity Fisher information as size = "fisher". These percentages are then converted to graphical dimensions using the same RevMan-style normalization applied under "sampsize_revman" and "se_revman".

"equal"

All studies shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

if TRUE, the HSROC curve is added to the plot. Default is TRUE.

conflevel

Confidence level for the study-level confidence intervals. Default is 0.95.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown using the selected symbol (rectangles by default).

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • HSROC curve

Value

No return value. Called for its side effect of producing a plot.

References

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

See Also

fitRutterGatsonis


Plot Results from a Rutter and Gatsonis LCA Model

Description

Produces a summary ROC plot for objects of class "RutterGatsonisLCA" obtained from fitRutterGatsonisLCA. Study-specific sensitivities and specificities are empirical Bayes estimates derived from the fitted latent class model.

Usage

## S3 method for class 'RutterGatsonisLCA'
plot(
  x,
  symbol = c("rectangle", "ellipse", "diamond", "triangle", "cross", "plus", "star"),
  scale = 0.02,
  size = c("eb", "equal", "sampsize", "eb_revman", "sampsize_revman"),
  specrange = c(0.7, 0.995),
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = TRUE,
  studyCI = FALSE,
  conflevel = 0.95,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "RutterGatsonisLCA", as returned by fitRutterGatsonisLCA.

symbol

Character string specifying the symbol used for study-level estimates. One of "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". The default is "rectangle".

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"eb"

Horizontal and vertical symbol dimensions are proportional to normalized inverse posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates, respectively.

"equal"

All studies are shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are both proportional to relative total study sample size. The same dimension measure is used horizontally and vertically because true disease status is latent.

"eb_revman"

RevMan-style graphical scaling applied to the inverse conditional posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension. This is an analogous graphical extension for latent-class models and is not an original Cochrane latent-class weighting method.

"sampsize_revman"

RevMan-style graphical scaling based on total study sample size. The same transformed total-sample-size measure is used horizontally and vertically.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

if TRUE, the HSROC curve is added to the plot. Default is TRUE.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

conflevel

Confidence level for the study-level confidence intervals. Default is 0.95.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown using the selected symbol (rectangles by default).

The following elements are displayed:

  • Study-level sensitivity and specificity estimates

  • HSROC curve

Value

No return value. Called for its side effect of producing a plot.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

See Also

fitRutterGatsonisLCA


Plot Results from a Rutter and Gatsonis Subgroup Model

Description

Produces summary ROC plots for objects of class "RutterGatsonisSubgroup" obtained from fitRutterGatsonisSubgroup. The plot displays study-level estimates of sensitivity and specificity, stratified by subgroup, together with subgroup-specific HSROC (hierarchical summary ROC) curves.

Usage

## S3 method for class 'RutterGatsonisSubgroup'
plot(
  x,
  symbol = NULL,
  scale = 0.02,
  size = c("equal", "fisher", "fisher_revman", "sampsize", "se", "sampsize_revman",
    "se_revman"),
  nudge_legend = -0.4,
  specrange = c(0.7, 0.995),
  col = NULL,
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = TRUE,
  connectstudies = FALSE,
  studyCI = FALSE,
  conflevel = 0.95,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "RutterGatsonisSubgroup", as returned by fitRutterGatsonisSubgroup.

symbol

Character vector specifying the symbols used for study-level estimates of the subgroups. One can choose "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". If NULL, symbols are generated automatically.

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"equal"

All studies shown with equal size. Default.

"fisher"

Displays parameter-specific percentage study contributions to the recovered subgroup-specific pooled logit sensitivity and logit specificity. Fisher sizing is available when HSROC accuracy and threshold parameters are subgroup-specific.

"fisher_revman"

Horizontal and vertical symbol dimensions are based on the same per-study percentage contributions to the logit sensitivity and logit specificity Fisher information as size = "fisher". These percentages are then converted to graphical dimensions using the same RevMan-style normalization applied under "sampsize_revman" and "se_revman".

"sampsize"

Horizontal and vertical symbol dimensions are proportional to the relative numbers of non-diseased and diseased participants, respectively.

"se"

Horizontal and vertical symbol dimensions are proportional to normalized approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively.

"sampsize_revman"

RevMan-style sample-size scaling. Horizontal and vertical symbol dimensions are based on the square roots of the numbers of non-diseased and diseased participants, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

"se_revman"

RevMan-style inverse-standard-error scaling. Horizontal and vertical symbol dimensions are based on approximate inverse standard errors of observed logit specificity and logit sensitivity, respectively. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension.

nudge_legend

Numeric horizontal offset for the subgroup legend. More negative values move the legend further right, outside the plotting area. Values closer to zero move it closer to the panel. Default is -0.4.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

col

Vector of colours used for subgroup-specific HSROC curves and study-level point estimates. If NULL, colours are generated automatically.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

if TRUE, the HSROC curve is added to the plot. Default is TRUE.

connectstudies

Whether the point estimates of two subgroups within the same study should be connected. Defaults to FALSE.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

conflevel

Confidence level for the study-level confidence intervals. Default is 0.95.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown with subgroup-specific symbols and colours.

The following elements are displayed:

  • Study-level sensitivity and specificity estimates by subgroup

  • Subgroup-specific HSROC curves

  • A legend identifying the subgroups

Value

No return value. Called for its side effect of producing a plot.

References

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

See Also

fitRutterGatsonisSubgroup


Plot Results from a Rutter and Gatsonis Subgroup LCA Model

Description

Produces summary ROC plots for objects of class "RutterGatsonisSubgroupLCA" obtained from fitRutterGatsonisSubgroupLCA. The plot displays study-level estimates of sensitivity and specificity (empirical Bayes estimates), stratified by subgroup, together with subgroup-specific HSROC (hierarchical summary ROC) curves.

Usage

## S3 method for class 'RutterGatsonisSubgroupLCA'
plot(
  x,
  symbol = NULL,
  scale = 0.02,
  size = c("eb", "equal", "sampsize", "eb_revman", "sampsize_revman"),
  nudge_legend = -0.4,
  specrange = c(0.7, 0.995),
  col = NULL,
  main = "Diagnostic Test Accuracy Meta-Analysis",
  HSROC = TRUE,
  connectstudies = FALSE,
  studyCI = FALSE,
  conflevel = 0.95,
  studylabels = FALSE,
  legend = TRUE,
  ...
)

Arguments

x

An object of class "RutterGatsonisSubgroupLCA", as returned by fitRutterGatsonisSubgroupLCA.

symbol

Character vector specifying the symbols used for study-level estimates of the subgroups. One can choose "rectangle", "ellipse", "diamond", "triangle", "cross", "plus", or "star". If NULL, symbols are generated automatically.

scale

Numeric scaling factor controlling study-symbol dimensions. The default is 0.02. Values below or above the default decrease or increase all symbol dimensions proportionally. Relative adjustments can be specified directly, for example, scale = 0.02 * 0.3 produces marker dimensions equal to 30 percent of the default.

size

Character string controlling display of study-level point estimates:

"eb"

Horizontal and vertical symbol dimensions are proportional to normalized inverse posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates, respectively.

"equal"

All studies are shown with equal size.

"sampsize"

Horizontal and vertical symbol dimensions are both proportional to relative total study sample size. The same dimension measure is used horizontally and vertically because true disease status is latent.

"eb_revman"

RevMan-style graphical scaling applied to the inverse conditional posterior standard errors of the study-specific empirical Bayes logit-specificity and logit-sensitivity estimates. A common analysis-specific scaling constant is chosen so that the average larger dimension measure across studies equals nine before adding the fixed baseline dimension. This is an analogous graphical extension for latent-class models and is not an original Cochrane latent-class weighting method.

"sampsize_revman"

RevMan-style graphical scaling based on total study sample size. The same transformed total-sample-size measure is used horizontally and vertically.

nudge_legend

Numeric horizontal offset for the subgroup legend. More negative values move the legend further right, outside the plotting area. Values closer to zero move it closer to the panel. Default is -0.4.

specrange

A numeric vector of length 2 giving the range of specificities over which the HSROC curve is plotted. Defaults to c(0.7, 0.995).

col

Vector of colours used for subgroup-specific HSROC curves and study-level point estimates. If NULL, colours are generated automatically.

main

Character string giving the main title of the plot. Defaults to "Diagnostic Test Accuracy Meta-Analysis".

HSROC

if TRUE, the HSROC curve is added to the plot. Default is TRUE.

connectstudies

Whether the point estimates of two subgroups within the same study should be connected. Defaults to FALSE.

studyCI

Whether study-level confidence intervals should be displayed for the observed sensitivity and specificity estimates. Defaults to FALSE.

conflevel

Confidence level for the study-level confidence intervals. Default is 0.95.

studylabels

Whether study identifiers should be displayed next to the study-level estimates. Defaults to FALSE.

legend

Whether a legend should be displayed. Default is TRUE.

...

Additional graphical arguments passed to plotting functions.

Details

The plot is constructed on the ROC scale with sensitivity on the y-axis and specificity on the x-axis (displayed as 1 - false positive rate on a reversed axis).

Study-specific estimates are shown with subgroup-specific symbols and colours.

The following elements are displayed:

  • Study-level sensitivity and specificity estimates by subgroup

  • Subgroup-specific HSROC curves

  • A legend identifying the subgroups

Value

No return value. Called for its side effect of producing a plot.

References

Liu, Y., Chen, Y., & Chu, H. (2015). A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard. Biometrics, 71(2), 538-547. doi:10.1111/biom.12264

Freeman, S. C., Kerby, C. R., Patel, A., Cooper, N. J., Quinn, T., & Sutton, A. J. (2019). Development of an interactive web-based tool to conduct and interrogate meta-analysis of diagnostic test accuracy studies: MetaDTA. BMC Medical Research Methodology, 19, 81. doi:10.1186/s12874-019-0724-x

Harbord, R. M., Deeks, J. J., Egger, M., Whiting, P., & Sterne, J. A. C. (2007). A unification of models for meta-analysis of diagnostic accuracy studies. Biostatistics, 8(2), 239–251. doi:10.1093/biostatistics/kxl004

See Also

fitRutterGatsonisSubgroupLCA


Print Method for HoyerAFT Objects

Description

Displays a concise summary of a fitted Hoyer AFT model, including distribution, number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'HoyerAFT'
print(x, ...)

Arguments

x

An object of class "HoyerAFT".

...

Further arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.HoyerAFT


Print Method for Reitsma Objects

Description

Displays a concise summary of a fitted Reitsma diagnostic test accuracy model, including number of studies, convergence status and likelihood-based fit statistics.

Usage

## S3 method for class 'Reitsma'
print(x, ...)

Arguments

x

An object of class "Reitsma".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.Reitsma


Print Method for ReitsmaLCA Objects

Description

Displays a concise summary of a fitted Reitsma LCA model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'ReitsmaLCA'
print(x, ...)

Arguments

x

An object of class "ReitsmaLCA".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.ReitsmaLCA


Print Method for ReitsmaSubgroup Objects

Description

Displays a concise summary of a fitted Reitsma Subgroup diagnostic test accuracy model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'ReitsmaSubgroup'
print(x, ...)

Arguments

x

An object of class "ReitsmaSubgroup".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.ReitsmaSubgroup


Print Method for ReitsmaSubgroupLCA Objects

Description

Displays a concise summary of a fitted ReitsmaSubgroupLCA model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'ReitsmaSubgroupLCA'
print(x, ...)

Arguments

x

An object of class "ReitsmaSubgroupLCA".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.ReitsmaSubgroupLCA


Print Method for ReitsmaSubgroupTMB Objects

Description

Displays a concise summary of a fitted ReitsmaSubgroupTMB diagnostic test accuracy model, including number of studies, convergence status and likelihood-based fit statistics.

Usage

## S3 method for class 'ReitsmaSubgroupTMB'
print(x, ...)

Arguments

x

An object of class "ReitsmaSubgroupTMB".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.ReitsmaSubgroupTMB


Print Method for ReitsmaTMB Objects

Description

Displays a concise summary of a fitted ReitsmaTMB diagnostic test accuracy model, including number of studies, convergence status and likelihood-based fit statistics.

Usage

## S3 method for class 'ReitsmaTMB'
print(x, ...)

Arguments

x

An object of class "ReitsmaTMB".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.ReitsmaTMB


Print Method for RutterGatsonis Objects

Description

Displays a concise summary of a fitted HSROC model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'RutterGatsonis'
print(x, ...)

Arguments

x

An object of class "RutterGatsonis".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.RutterGatsonis


Print Method for RutterGatsonisLCA Objects

Description

Displays a concise summary of a fitted HSROC LCA model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'RutterGatsonisLCA'
print(x, ...)

Arguments

x

An object of class "RutterGatsonisLCA".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.RutterGatsonisLCA


Print Method for RutterGatsonisReg Objects

Description

Displays a concise summary of a fitted HSROC model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'RutterGatsonisReg'
print(x, ...)

Arguments

x

An object of class "RutterGatsonisReg".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.RutterGatsonisReg


Print Method for RutterGatsonisSubgroup Objects

Description

Displays a concise summary of a fitted HSROC model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'RutterGatsonisSubgroup'
print(x, ...)

Arguments

x

An object of class "RutterGatsonisSubgroup".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.RutterGatsonisSubgroup


Print Method for RutterGatsonisSubgroupLCA Objects

Description

Displays a concise summary of a fitted RutterGatsonisSubgroupLCA model, including number of studies, convergence status, and likelihood-based fit statistics.

Usage

## S3 method for class 'RutterGatsonisSubgroupLCA'
print(x, ...)

Arguments

x

An object of class "RutterGatsonisSubgroupLCA".

...

Additional arguments (unused).

Value

Invisibly returns the input object.

See Also

summary.RutterGatsonisSubgroupLCA


Print a Diagnostic Test Accuracy Model Summary

Description

Prints summary objects returned by summary() methods for diagnostic test accuracy models.

Usage

## S3 method for class 'summary.DTAmodel'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.HoyerAFT'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.Reitsma'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.ReitsmaTMB'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.ReitsmaLCA'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.ReitsmaSubgroup'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.ReitsmaSubgroupTMB'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.ReitsmaSubgroupLCA'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.RutterGatsonis'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.RutterGatsonisReg'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.RutterGatsonisLCA'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.RutterGatsonisSubgroup'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

## S3 method for class 'summary.RutterGatsonisSubgroupLCA'
print(x, digits = max(8L, getOption("digits") - 8L), ...)

Arguments

x

A summary object inheriting from "summary.DTAmodel".

digits

Number of significant digits used for printing.

...

Additional arguments passed to printing methods.

Value

Invisibly returns x.


Construct Interval Data for Threshold-Based Bivariate Time-to-Event Models

Description

Transforms study-level diagnostic test accuracy (DTA) data with multiple thresholds into interval-censored format suitable for likelihood-based modelling (Hoyer et al., 2018).

Usage

restructure_data(
  data,
  TP,
  FP,
  FN,
  TN,
  threshold,
  study,
  smallest,
  largest,
  testdirection = c("greater", "less")
)

Arguments

data

A data.frame containing study-level data.

TP

True positives (column name).

FP

False positives (column name).

FN

False negatives (column name).

TN

True negatives (column name).

threshold

The observed threshold value (column name). Must be positive and strictly increasing within each study.

study

Study identifier (column name).

smallest

Positive lower bound used to define the leftmost interval. Must be smaller than minimum threshold.

largest

Positive upper bound used to define the rightmost interval. Must be greater than maximum threshold.

testdirection

Direction of the test. Enter "greater" when larger test values indicate disease. Conversely, enter "less" when lower test values indicate disease (e.g. anaemia-type tests). Defaults to "greater".

Details

The function constructs:

  • A left-censored interval (below the first threshold)

  • Intermediate intervals between adjacent thresholds

  • A right-censored interval (above the last threshold)

Event counts are derived from cumulative counts to represent the number of observations falling within each interval for diseased and non-diseased groups. Therefore, input counts must be cumulative over increasing thresholds within each study.

The function first validates that counts are numeric, non-negative integers and that threshold values are positive.

Within each study, total numbers of diseased (n1) and non-diseased (n0) individuals are required to be constant across thresholds. Intermediate interval counts are computed as differences between cumulative counts.

The log-scale midpoint (lcutmean) is provided to support initialization of random effects in subsequent Hoyer AFT models.

For testdirection = "greater", the function assumes that sensitivity decreases and specificity increases with increasing thresholds. For testdirection = "less", the reverse monotonicity is required. Internally, the function standardizes the definition of a positive test result so that it always corresponds to values above the threshold. For testdirection = "less", this is achieved by relabeling the observed counts. This does not affect the resulting sensitivity, specificity, or ROC curve, but ensures compatibility with the model formulation.

Value

A list with two components:

restructured

A data frame with one row per constructed interval containing:

study

Study identifier

TP, TN, n1, n0

Original counts carried forward

threshold

Threshold associated with the interval

lowerB

Lower interval bound (NA for left-censored)

upperB

Upper interval bound (NA for right-censored)

events1

Number of diseased observations in the interval

events0

Number of non-diseased observations in the interval

ctype

Censoring type (1 = left, 2 = interval, 3 = right)

lcutmean

Midpoint of log-thresholds defining the interval

original

The processed original data including (derived) quantities:

n1

Total number of diseased individuals (TP + FN)

n0

Total number of non-diseased individuals (TN + FP)

sens

Sensitivity (TP / n1)

spec

Specificity (TN / n0)

fpr

False positive rate (FP / n0)

testdirection

As specified by testdirection

References

Hoyer, A., Hirt, S., Kuss, O. (2018). Meta-analysis of full ROC curves using bivariate time-to-event models for interval-censored data. Research Synthesis Methods, 9(1), 62-72. doi:10.1002/jrsm.1273

Examples

data("diabetes")
res <- restructure_data(
  data = diabetes,
  TP = TP,
  FP = FP,
  FN = FN,
  TN = TN,
  threshold = threshold,
  study = study,
  smallest = 2,
  largest = 10
)

RF Dataset

Description

This is the RF dataset from Nishimura (2007) from a review of rheumatoid factor (RF) to diagnose rheumatoid arthritis.

Usage

RF

Format

A data frame with 50 rows and 8 variables:

study

Study identifier

year

Year of the study

TP

Number of true positives

FP

Number of false positives

FN

Number of false negatives

TN

Number of true negatives

cutoff

Threshold used in U/mL for test positivity

method

Different methods used to perform the test

Source

Nishimura, K. et al. (2007). Meta-analysis: diagnostic accuracy of anti-cyclic citrullinated peptide antibody and rheumatoid factor for rheumatoid arthritis. Annals of Internal Medicine, 146(11), 392-403. doi:10.7326/0003-4819-146-11-200706050-00008


Schuetz Dataset

Description

This is the schuetz dataset from Schuetz (2010) from a meta-analysis of non-invasive coronary angiography using computer tomography (CT) versus magnetic resonance imaging (MRI)

Usage

schuetz

Format

A data frame with 108 rows and 7 variables:

test

Which test was used, CT or MRI

study

Study identifier

TP

Number of true positives

FP

Number of false positives

FN

Number of false negatives

TN

Number of true negatives

indirect

whether the comparison is indirect (=1) or direct (=0)

Source

Schuetz, K., et al. (2010). Meta‐analysis: noninvasive coronary angiography using computer tomography versus magnetic resonance imaging. Annals of Internal Medicine, 152(3), 167-177. doi:10.7326/0003-4819-152-3-201002020-00008


Summary Method for HoyerAFT Objects

Description

Extracts and returns the summary information stored in a fitted HoyerAFT model object.

Usage

## S3 method for class 'HoyerAFT'
summary(object, ...)

Arguments

object

An object of class "HoyerAFT", typically the result of a call to fitHoyerAFT.

...

Additional arguments (currently unused).

Details

This method is part of the standard S3 summary() generic and provides access to summary statistics computed from the fitted model, as stored in the sdreport2 and sensspec component of the object.

Value

A list of class "summary.HoyerAFT" with two data frames containing summary statistics derived from the fitted model.

  • sdreport2: Parameter estimates with standard errors as returned from TMB reported parameters.

  • sensspec: Estimated sensitivity and specificity with confidence intervals at the specified thresholds.

See Also

fitHoyer fitHoyerAFT


Summary Method for Reitsma Objects

Description

Extracts key results from an object of class "Reitsma", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'Reitsma'
summary(object, ...)

Arguments

object

An object of class "Reitsma" as returned by fitReitsma.

...

Additional arguments (currently ignored).

Value

A list of class "summary.Reitsma" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated sensitivity and specificity with confidence intervals.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

See Also

fitReitsma


Summary Method for ReitsmaLCA Objects

Description

Extracts key results from an object of class "ReitsmaLCA", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'ReitsmaLCA'
summary(object, ...)

Arguments

object

An object of class "ReitsmaLCA" as returned by fitReitsmaLCA.

...

Additional arguments (currently ignored).

Value

A list of class "summary.ReitsmaLCA" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated sensitivity and specificity with confidence intervals.

  • prevref: Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

See Also

fitReitsmaLCA


Summary Method for ReitsmaSubgroup Objects

Description

Extracts key results from an object of class "ReitsmaSubgroup", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'ReitsmaSubgroup'
summary(object, ...)

Arguments

object

An object of class "ReitsmaSubgroup" as returned by fitReitsmaSubgroup.

...

Additional arguments (currently ignored).

Value

A list of class "summary.ReitsmaSubgroup" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated sensitivity and specificity with confidence intervals.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • subgroups Subgroup names.

See Also

fitReitsmaSubgroup


Summary Method for ReitsmaSubgroupLCA Objects

Description

Extracts key results from an object of class "ReitsmaSubgroupLCA", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'ReitsmaSubgroupLCA'
summary(object, ...)

Arguments

object

An object of class "ReitsmaSubgroupLCA" as returned by fitReitsmaSubgroupLCA.

...

Additional arguments (currently ignored).

Value

A list of class "summary.ReitsmaSubgroupLCA" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated sensitivity and specificity with confidence intervals.

  • prevref: Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

See Also

fitReitsmaSubgroupLCA


Summary Method for ReitsmaSubgroupTMB Objects

Description

Extracts key results from an object of class "ReitsmaSubgroupTMB", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'ReitsmaSubgroupTMB'
summary(object, ...)

Arguments

object

An object of class "ReitsmaSubgroupTMB" as returned by fitReitsmaSubgroupTMB.

...

Additional arguments (currently ignored).

Value

A list of class "summary.ReitsmaSubgroupTMB" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated sensitivity and specificity with confidence intervals.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

  • subgroups Subgroup names.

See Also

fitReitsmaSubgroupTMB


Summary Method for ReitsmaTMB Objects

Description

Extracts key results from an object of class "ReitsmaTMB", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'ReitsmaTMB'
summary(object, ...)

Arguments

object

An object of class "ReitsmaTMB" as returned by fitReitsmaTMB.

...

Additional arguments (currently ignored).

Value

A list of class "summary.ReitsmaTMB" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated sensitivity and specificity with confidence intervals.

  • RutterGatsonis_recovered: Recovered parameters in the Rutter-Gatsonis (HSROC) parameterization.

See Also

fitReitsmaTMB


Summary Method for RutterGatsonis Objects

Description

This method extracts key components from a fitted HSROC model object returned by fitRutterGatsonis. It returns parameter estimates, sensitivity/specificity summaries, and the recovered Reitsma parameterization.

Usage

## S3 method for class 'RutterGatsonis'
summary(object, ...)

Arguments

object

An object of class "RutterGatsonis" as returned by fitRutterGatsonis.

...

Additional arguments (currently unused).

Details

Provides a concise summary of a fitted "RutterGatsonis" model.

Value

A list of class "summary.RutterGatsonis" containing the following components:

  • estimates Parameter estimates with standard errors as returned from TMB reported parameters.

  • sensspec Estimated sensitivity at the specified specificity, including confidence intervals.

  • Reitsma_recovered Recovered parameters in the Reitsma parameterization.

See Also

fitRutterGatsonis


Summary Method for RutterGatsonisLCA Objects

Description

This method extracts key components from a fitted HSROC model object returned by fitRutterGatsonisLCA. It returns parameter estimates, sensitivity/specificity summaries, and the recovered Reitsma parameterization.

Usage

## S3 method for class 'RutterGatsonisLCA'
summary(object, ...)

Arguments

object

An object of class "RutterGatsonisLCA" as returned by fitRutterGatsonisLCA.

...

Additional arguments (currently unused).

Details

Provides a concise summary of a fitted "RutterGatsonisLCA" model.

Value

A list of class "summary.RutterGatsonisLCA" containing the following components:

  • estimates: Parameter estimates with standard errors as returned from TMB reported parameters.

  • sensspec: Estimated index test sensitivity at the specified specificity, including confidence intervals.

  • prevref: Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

  • Reitsma_recovered: Recovered parameters in the Reitsma parameterization.

See Also

fitRutterGatsonisLCA


Summary Method for RutterGatsonisReg Objects

Description

This method extracts key components from a fitted HSROC model object returned by fitRutterGatsonisReg. It returns parameter estimates, sensitivity/specificity summaries.

Usage

## S3 method for class 'RutterGatsonisReg'
summary(object, ...)

Arguments

object

An object of class "RutterGatsonisReg" as returned by fitRutterGatsonisReg.

...

Additional arguments (currently unused).

Details

Provides a concise summary of a fitted "RutterGatsonisReg" model.

Value

A list of class "summary.RutterGatsonisReg" containing the following components:

  • estimates Parameter estimates with standard errors as returned from TMB reported parameters.

  • sensspec Estimated sensitivity at the specified specificity, including confidence intervals.

See Also

fitRutterGatsonisReg


Summary Method for RutterGatsonisSubgroup Objects

Description

This method extracts key components from a fitted HSROC model object returned by fitRutterGatsonisSubgroup. It returns parameter estimates and sensitivity/specificity summaries.

Usage

## S3 method for class 'RutterGatsonisSubgroup'
summary(object, ...)

Arguments

object

An object of class "RutterGatsonisSubgroup" as returned by fitRutterGatsonisSubgroup.

...

Additional arguments (currently unused).

Details

Provides a concise summary of a fitted "RutterGatsonisSubgroup" model.

Value

A list of class "summary.RutterGatsonisSubgroup" containing the following components:

  • estimates Parameter estimates with standard errors as returned from TMB reported parameters.

  • sensspec Estimated sensitivity at the specified specificity, including confidence intervals.

  • Reitsma_recovered Recovered parameters in the Reitsma parameterization.

  • subgroups Subgroup names.

See Also

fitRutterGatsonisSubgroup


Summary Method for RutterGatsonisSubgroupLCA Objects

Description

Extracts key results from an object of class "RutterGatsonisSubgroupLCA", including parameter estimates, sensitivity and specificity summaries, and recovered HSROC parameters from the Rutter–Gatsonis parameterization.

Usage

## S3 method for class 'RutterGatsonisSubgroupLCA'
summary(object, ...)

Arguments

object

An object of class "RutterGatsonisSubgroupLCA" as returned by fitRutterGatsonisSubgroupLCA.

...

Additional arguments (currently ignored).

Value

A list of class "summary.RutterGatsonisSubgroupLCA" with the following components:

  • estimates: Parameter estimates with standard errors.

  • sensspec: Estimated index test sensitivity at the specified specificity, including confidence intervals.

  • prevref: Estimated (average) prevalence and reference standard sensitivity/specificity with confidence intervals.

  • Reitsma_recovered: Recovered parameters in the Reitsma parameterization.

See Also

fitRutterGatsonisSubgroupLCA


Tub Dataset

Description

This is the tub dataset from Kohli et al. (2018) from a meta-analysis examining the accuracy of the GeneXpert test for tuberculosis meningitis. In each study the index test was GeneXpert and the (imperfect) reference standard was culture.

Usage

tub

Format

A data frame with 29 rows and 5 variables:

id

Study identifier

y11

Number testing positive with both tests

y10

Number testing positive with index test but negative with reference test

y01

Number testing negative with index test but positive with reference test

y00

Number testing negative with both tests

Note

The dataset was taken from the supplementary material of the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy Studies.

Source

Deeks, J. J., Bossuyt, P. M., Leeflang, M. M., & Takwoingi, Y. (editors) (2023). Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy. Version 2.0 (updated July 2023). Cochrane.

Kohli, M. et al. (2018). Xpert MTB/RIF assay for extrapulmonary tuberculosis and rifampicin resistance. Cochrane Database of Systematic Reviews 2018, 8, CD012768. doi:10.1002/14651858.CD012768.pub2


Extract Variance-Covariance Matrix

Description

Returns the variance-covariance matrix of the estimated model parameters.

Usage

## S3 method for class 'DTAmodel'
vcov(object, ...)

## S3 method for class 'Reitsma'
vcov(object, ...)

## S3 method for class 'ReitsmaSubgroup'
vcov(object, ...)

## S3 method for class 'ReitsmaLCA'
vcov(object, ...)

## S3 method for class 'ReitsmaSubgroupLCA'
vcov(object, ...)

Arguments

object

A fitted model object.

...

Not currently used.

Value

A variance-covariance matrix corresponding to the parameters returned by coef().

Note

For ReitsmaSubgroup models, the returned variance-covariance matrix corresponds to the cell-means parameterization returned by coef().

See Also

coef.dtametaTMB()