Exact Inferences of the Youden Index

• Activity Number: 126
• Type: Contributed
• Date/Time: Monday, August 2, 2010 : 8:30 AM to 10:20 AM
• Sponsor: Biometrics Section
• Author(s): Chin-Ying Lai*+ and Enrique F. Schisterman and Lili Tian
• Companies: State University of New York at Buffalo and Eunice Kennedy Shriver National Institute of Child Health and Human Development and State University of New York at Buffalo
• Keywords: ROC Curve ; Generalized Pivotal Quantity ; Generalized Test Variable ; Youden Index

Abstract

In diagnostic studies, the Receiver Operating Characteristic (ROC) curve and its area under the ROC curve are important tools in assessing the discriminating ability of biomarkers or diagnostic ability of tests between non-diseased and diseased populations. In order to classify a patient into non-diseased or diseased groups, an optimal cut-point of a continuous biomarker is desirable. Youden's index (J), defined as the maximum vertical distance between the ROC curve and the diagonal chance line, serves as another global measure of overall diagnostic accuracy and can be used to choose an optimal cut-off point. In this talk, we propose to use the concepts of generalized pivotal quantity and generalized test variable to make inferences about the cut-off point and Youden index. Simulation study results will also be presented.