Dear List,
I am trying to assess the prediction accuracy of an ordinal model fit with LRM in the Design package. I used predict.lrm to predict on an independent dataset and am now attempting to assess the accuracy of these predictions. >From what I have read, the AUC is good for this because it is threshold independent. I obtained the AUC for the fit model output from the c score (c = 0.78). For the predicted values and independent data, for each level of the response I used the ROCR functions to get the AUC (i.e., probability y >= class1, y >= class2, y >= class3 etc) and plotted the ROC curves for each. The AUC values are all higher (AUC = 0.80 - 0.93) for the predicted values than what I got from the fit model in lrm. I am not sure whether I have misinterpreted the use of the AUC for ordinal models or whether the prediction results are actually better than the model results. Any help / clarification appreciated, Colin Colin Robertson University of Victoria [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list 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.