Hi I am new to SAS and need suggestions on my  codes.   I wanted to compare two logistic regression models. I tried to use 10-fold cross-validation for both models. I first searched online and find below code which can generate different folds and run logistic regression on my training data sets. But I do not know how I can use the training model to predict and compare my test data set. If possible, I wanted to draw ROC and calculate the AUC.   I attached current codes here. Please help me for my next step. Thanks very much!   %let K=10; %let rate=%sysevalf((&K-1)/&K); *Build model with all data; proc logistic data=cold; model y(event="1")=temp time time*temp; run; *Generate the cross validation sample; proc surveyselect data=cold out=cv seed=231258 samprate=&rate outall reps=10; run; /* the variable selected is an automatic variable generatic by surveyselect.*/ /*If selected is true then then new_y will get the value of y otherwise is missing */ data cv; set cv; if selected then new_y=y; run; /* get predicted values for the missing new_y in each replicate */ ods output ParameterEstimates=ParamEst; proc logistic data=cv; model new_y(event="1")=temp time time*temp/outroc=roc; by replicate; output out=out1(where=(new_y=.)) predicted=y_hat; run; ... View more