Use the drop-down menu to indicate the method by which to partition the observations for cross validation .
Choose this method to request parts be formed of k blocks of consecutive observations. Choose this option to request that the i th part consists of observations i , i + k , i + 2 k , .... Note : You can also use an index variable to define the CV splits. For this, specify CVMETHOD=INDEX(index variable) in the PROC GLMSELECT Modeling Options field on the Options tab.