You do not have a DATA= option on the PROC statement which data set to use. By default it uses the last run data set, which is likely not what you want in this case since it doesn't have the variables. This is a style of programming I would never recommend, it's always better to explicitly specify the data set used in a procedure.    @hdrew wrote: I am using this SAS code for Variable Summary report and receiving an error message:  log is telling me the variable "auto" and "v1" doesn't exist   following SAS Code: ods graphics on; proc cluster data=inputDataSet method=average std pseudo noeigen outtree=tree; id auto; var v1-v4; run; proc tree data=tree horizontal; run;   ... View more