> -----Original Message----- > From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On > Behalf Of Orin Richards > Sent: Sunday, August 09, 2009 12:42 PM > To: SAS-L@LISTSERV.UGA.EDU > Subject: Proc GLM and Categorical variables > > Hi All, > I am using PROC GLM to do some analysis on age and treatment > (treat). Now treat is my categorical variable and age my > continuous variable. The categorical variable treat has the > followin levels high, low and control. By default PROC GLM > uses alphabethical ordering to determine the reference > category, therefore in my case "low" is the reference > category. I would like to know if there is a way to tell > PROC GLM to use" control" as the reference category. I can > create a new treatrment variable give the the appropriate > names so that "control" is the reference category. I would > however like to know if PROC GLM has an option that allows > you tell it what you would like the reference category to be. > > Thanks > > Orin

You don't don’t show your code , or example data, but you should be able to use ref='control' on the class statement. Something like

proc glm data=have; class treat(ref='control'); model y = treat / solution; quit;

Hope this is helpful,

Dan

Daniel Nordlund Bothell, WA USA