Are Risk Stratification Tables the Best Way to Evaluate Model Performance?
IN RESPONSE: We thank Drs. Stern and Smith for their thoughts on improving methods for the evaluation of risk prediction models. We agree wholeheartedly that the distribution of risks predicted by the risk prediction model is key for evaluating model performance. In the statistical literature, this has been called the predictiveness curve, and we have advocated strongly for its use (1, 2). In fact, the margins of a risk stratification table display exactly this: the population distribution of risk according to the 2 models, albeit by using discrete categories. Because the main goal of our article is to emphasize that one should focus on the margins of the risk stratification table rather than the interior cells, our article in fact concurs with the point of view of Drs. Stern and Smith. The area under the ROC curve or c-statistic can indeed be viewed as a measure of the dispersion of the risk distribution. However, it seems to be a measure that lacks clinical relevance (3, 4). In addit
