You are right. I tried with SAS in another computer and ORDER=DATA works... weird...   Thanks so much for your help. ... View more

Thanks.  I have tried to re-order by using PROC SORT but it still takes stage 4 as the reference group.   I will try the PROC FORMAT method later.   Thanks again ... View more

OK... Thanks for your help. Really appreciate it. ... View more

I see....   proc lifereg data=larynx order=data; class stage; model deathtime*death(0)=stage / distribution=exponential; run;   but it still uses stage 4 as my reference group, not stage 1.     ... View more

Thanks for your reply.   I tried this   proc lifereg data=larynx; class stage/ order=data; model deathtime*death(0)=stage / distribution=exponential; run;   I also tried just    class stage/ order;   but still didnt work. and this is what i got   12 class stage/ order=data; ----- 22 202 NOTE: The previous statement has been deleted. NOTE: PROCEDURE LIFEREG used (Total process time): real time 0.04 seconds cpu time 0.04 seconds NOTE: The SAS System stopped processing this step because of errors. ERROR 22-322: Syntax error, expecting one of the following: ;, TRUNCATE. ERROR 202-322: The option or parameter is not recognized and will be ignored. ... View more