Xc. Pan et Ce. Metz, THE PROPER BINORMAL MODEL - PARAMETRIC RECEIVER OPERATING CHARACTERISTIC CURVE ESTIMATION WITH DEGENERATE DATA, Academic radiology, 4(5), 1997, pp. 380-389
Rationale and Objectives. The authors assessed the use of a ''proper''
binormal model and a new algorithm for maximum-likelihood estimation
of receiver operating characteristic (ROC) curves from degenerate data
. Methods. The proper binormal ROC model uses as its decision variable
a monotonic transformation of the likelihood ratio that is associated
with a pair of normal distributions, thereby ensuring fitted ROC curv
es with monotonic slope but maintaining a relationship with the conven
tional binormal model. A computer program entitled PROPROC was used to
fit proper ROC curves to data obtained from computer-simulated and re
al observer studies. Results. ROC indexes such as total area were esti
mated with PROPROC and compared with the corresponding values obtained
from the conventional procedures. Conclusion. The proper binormal ROC
model overcomes the problem of degeneracy in ROC curve fitting. PROPR
OC is highly robust and yields ROC estimates with less bias and greate
r precision than those obtained with the conventional binormal model.