The search-model
The search model is based on the Kundel-Nodine model of the diagnostic interpretation process, i.e., it is based on actual measurements and is not just a mathematically convenient model. It predicts ROC, LROC, AFROC and FROC curves. The ROC model cannot predict LROC, FROC and AFROC curves. The search model predicted ROC curves are always proper - unlike older ROC models, that are still used to analyze ROC data -they never cross the chance diagonal.The model is used in the plotting and sample-size estimation capabilities of the software.
For further details see my two papers in Physics of Medicine and Biology ; e-mail me if you need pdfs.