Rationale and objectives: The purpose of this study was to describe a simple bootstrap approach for estimating sensitivity, specificity, and the area under the receiver operating characteristic curve for multisite test outcome data.
Materials and methods: The performance of bootstrap estimates was evaluated and compared with that of analytic estimates by using a simulation study. Bootstrapping was demonstrated by using data from a previous study comparing two angiographic methods.
Results: Analytic and bootstrap estimates had similar coverage rates for 95% confidence intervals. With many sites per patient, bootstrap estimates had slightly better coverage than analytic estimates. Bootstrap percentile intervals had better coverage than asymptotic normal bootstrap intervals.
Conclusion: Bootstrapping is a useful method of estimating confidence intervals for the area under the receiver operating characteristic curve, sensitivity, and specificity when data are correlated.