Application of decision curve analysis to a case-control study. Decision curves for a simple model, a complex model, the reference strategies to treat none or all, and a hypothetical perfect prediction model based on the overall net benefit for an assumed true prevalence of π
0 = 0.15 (a), π
0 = 0.45 (b) and π
0 = 0.30 (c), the latter corresponding to the empirical prevalence π. While (c) is a reasonable assumption if the data are representative of the population of interest, this may no longer be the case if the data originate from a case-control study.