FitCorCbm.RdFit the Correlated Contaminated Binormal Model (CORCBM) to a paired ROC dataset. The ROC dataset has to be formatted as a single modality, two-reader dataset, even though the actual pairing may be different, see details.
FitCorCbm(dataset)A list containing three objects:
list(FPCounts,TPCounts,
muX,muY,alphaX,alphaY,rhoNor,
rhoAbn2,zetaX,zetaY,covMat,fixParam)
list(aucX,aucX,stdAucX,
stdAucY,stdErr,areaStat,areaPval)
The fitted plot with operating points, error bars, for both conditions
The conditions (X, Y) can be two readers interpreting images in the same
modality, the same reader interpreting images in different treatments, or
different readers interpreting images in 2 different treatments. Function
DfExtractCorCbmDataset can be used to construct a dataset suitable for
FitCorCbm. With reference to the returned values, and assuming R bins
in condition X and L bins in conditon Y,
FPCounts is the R x L matrix containing the counts for non-diseased cases,
TPCounts is the R x L matrix containing the counts for diseased cases;
muX,muY,alphaX,alphaY,rhoNor,rhoAbn2 are
the CORCBM parameters; aucX,aucX are the AUCs in the two conditions;
stdAucX,stdAucY are the corresponding standard errors;stdErr
contains the standard errors of the parameters of the model; areaStat,
areaPval,covMat are the area-statistic, the p-value and the covariance
matrix of the parameters. If a parameter approaches a limit, e.g., rhoNor
= 0.9999, it is held constant at near the limiting value and the covariance matrix
has one less dimension (along each edge) for each parameter that is held constant.
The indices of the parameters held fixed are in fitCorCbmRet$fixParam.
Zhai X, Chakraborty DP (2017) A bivariate contaminated binormal model for robust fitting of proper ROC curves to a pair of correlated, possibly degenerate, ROC datasets. Medical Physics. 44(6):2207–2222.