Optimal Weight in Estimating the Receiver Operating Characteristic Curve Area Using Longitudinal Data

• Activity Number: 253
• Type: Contributed
• Date/Time: Monday, August 2, 2010 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Yougui Wu*+
• Companies: University of South Florida
• Keywords: Repeated Biomarkers ; Optimal Weight ; ROC ; Sensitivity ; Specificity

Abstract

In the setting of longitudinal study, subjects are followed for the occurrence of some dichotomous outcome. In many of these studies, some biomarkers are also obtained repeatedly during the study period. Emir et al.(2000) introduced a non-parametric approach to the estimation of the area under the ROC curve of a repeated biomarker. Their nonparametric estimate involves assigning a weight to each subject. There are two weighting schemes suggested in their paper: one for the case when within-patient correlation is low, and the other for the case when within-subject correlation is high. However, it is not clear how to assign weights to biomarker measurements when within-patient correlation is modest. In this paper, we consider the optimal weights that minimizes the variance of the estimate of the area under the ROC curve of a repeated biomarker proposed by Emir et al.(2000).