title: Generalized Roe and Metz receiver operating characteristic model: analytic link between simulated decision scores and empirical AUC variances and covariances.
abstract: Modeling and simulation are often used to understand and investigate random quantities and estimators. In 1997, Roe and Metz introduced a simulation model to validate analysis methods for the popular endpoint in reader studies to evaluate medical imaging devices, the reader-averaged area under the receiver operating characteristic (ROC) curve. Here, we generalize the notation of the model to allow more flexibility in recognition that variances of ROC ratings depend on modality and truth state. We also derive and validate equations for computing population variances and covariances for reader-averaged empirical AUC estimates under the generalized model. The equations are one-dimensional integrals that can be calculated using standard numerical integration techniques. This work provides the theoretical foundation and validation for a Java application called iRoeMetz that can simulate multireader multicase ROC studies and numerically calculate the corresponding variances and covariances of the empirical AUC. The iRoeMetz application and source code can be found at the "iMRMC" project on the google code project hosting site. These results and the application can be used by investigators to investigate ROC endpoints, validate analysis methods, and plan future studies.
authors.affiliation: CDRH/FDA , Division of Imaging and Applied Mathematics, Bldg. 62, Rm 3124, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993-0002, United States.
authors.forename: Brandon D
authors.initials: BD
authors.lastname: Gallas
authors.affiliation: University of Iowa , Departments of Radiology and Biostatistics, 3170 Medical Laboratories, 200 Hawkins Drive, Iowa City, Iowa 52242-1077, United States ; Comprehensive Access and Delivery Research and Evaluation Center , VA Health Care System, Iowa City, Iowa 52242-1077, United States.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Hillis
keywords: medical imaging; multireader multicase; radiology; reader studies; receiver operating characteristic curves; simulations