Dear all, I am calculating the optimal cut-off for a test against a gold standard measure. I can determine the cut-off (in the following example 5.905) but I would like to assign it to an atomic variable so that the cut-off is updated every time the data is changed. I am using the ROC and roc functions of the packages Epi and pROC respectively. Would you know how to extract the optimal cut-off from these functions or a similar way to get such value? Best regards Luigi
>>> query.test <- c(5.43, 6.63, 0, 6.2, 5.61, 0, 5.59, 0, 0, 5.49, 18.35, 0, 6.07, 4.54, 4.73, 0, 5.74, 33.02, 4.45, 31.16, 0, 0, 3.12, 0, 0, 4.78, 0, 0, 0, 0, 0, 32.42 ) gold.std <- c(0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 ) df <- data.frame(cbind(query.test, gold.std)) library(Epi) library(pROC) # Epi ROC(form=gold.std ~ query.test, plot="ROC", data=df, MI=FALSE, MX=FALSE, PV=TRUE) # pROC roc(gold.std ~ query.test, df, smooth=FALSE, plot=TRUE, auc.polygon=TRUE, max.auc.polygon=TRUE, grid=TRUE, print.auc=TRUE, print.thres="best") ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.