Confidence Intervals for the Youden Index and Corresponding Optimal Cut-Point |
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| Authors: | Enrique F. Schisterman Neil Perkins |
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| Affiliation: | 1. Division of Epidemiology, Statistics and Prevention Research , National Institute of Child Health and Human Development (NICHD) , Bethesda, Maryland, USA;2. National Institutes of Health, Department of Health and Human Services , Bethesda, Maryland, USA schistee@mail.nih.gov;4. National Institutes of Health, Department of Health and Human Services , Bethesda, Maryland, USA;5. Department of Mathematics and Statistics , American University , Washington, DC |
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| Abstract: | A global measure of biomarker effectiveness is the Youden index, the maximum difference between sensitivity, the probability of correctly classifying diseased individuals, and 1-specificity, the probability of incorrectly classifying healthy individuals. The cut-point leading to the index is the optimal cut-point when equal weight is given to sensitivity and specificity. Using the delta method, we present approaches for estimating confidence intervals for the Youden index and corresponding optimal cut-point for normally distributed biomarkers and also those following gamma distributions. We also provide confidence intervals using various bootstrapping methods. A comparison of interval width and coverage probability is conducted through simulation over a variety of parametric situations. Confidence intervals via delta method are shown to have both closer to nominal coverage and shorter interval widths than confidence intervals from the bootstrapping methods. |
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| Keywords: | Confidence intervals Optimal cut-point ROC curve Sensitivity and specificity Youden index |
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