The c-index is not proper for the evaluation of $t$-year predicted risks
The c-index is not proper for the evaluation of $t$-year predicted risks
We show that the widely used concordance index for time to event outcome is not proper when interest is in predicting a $t$-year risk of an event, for example 10-year mortality. In the situation with a fixed prediction horizon, the concordance index can be higher for a misspecified model than …