As new biomarkers and risk prediction procedures are in rapid development, it is of great interest to develop valid methods for comparing predictive power of 2 biomarkers or risk score… Click to show full abstract
As new biomarkers and risk prediction procedures are in rapid development, it is of great interest to develop valid methods for comparing predictive power of 2 biomarkers or risk score systems. Harrell C statistic has been routinely used as a global adequacy assessment of a risk score system, and the difference of 2 Harrell C statistics as a test statistic has been suggested in recent literature for comparison of predictive power of 2 biomarkers for censored outcome. In this study, we showed that such a test can have severely inflated type I errors as the difference between the 2 Harrell C statistics does not converge to zero under the null hypothesis of equal predictive power measured by concordance probabilities, as illustrated by 2 counterexamples and corresponding numerical simulations. We further investigate a necessary and sufficient condition under which the difference of 2 Harrell C statistics converges to zero under the null hypothesis.
               
Click one of the above tabs to view related content.