Should I show FROC or AFROC curves? I strongly recommend showing the wAFROC since the area under this curve is the figure of merit that is being used in JAFROC analysis. The prevailing custom of showing the FROC is incorrect. The FROC is an open ended curve, and one does not know how far to the right and how far up (limit unity) it really extends. Unlike the FROC, the AFROC is fully contained within the unit square and a valid area measure can be defined.