摘要：A two-stage procedure for estimating sensitivity and specificity is described. The procedure is developed in the context of a validation study for self-reported atypical nevi, a potentially useful measure in the study of risk factors for malignant melanoma. The first stage consists of a sample of N individuals classified only by the test measure. The second stage is a subsample of size m, stratified according the information collected in the first stage, in which the presence of atypical nevi is determined by clinical examination. Using missing data methods for contingency tables, maximum likelihood estimators for the joint distribution of the test measure and the "gold standard" clinical evaluation are presented, along with efficient estimators for the sensitivity and specificity. Asymptotic coefficients of variation are computed to compare alternative sampling strategies for the second stage. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (672K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 11 12 13 14
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