Date:         Wed, 23 Jun 2010 14:10:28 -0700
Reply-To:     mlhoward@avalon.net
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Mary <mlhoward@AVALON.NET>
Subject:      Re: proc mixed levels, one level missing
Comments: To: Arthur Westover <anwestover@SBCGLOBAL.NET>
Content-Type: text/plain; charset="UTF-8"

Given that it is one less, one suspect cause might be the way it is creating dummy variables between the two procedures; in logistic it will create the same number of dummy variables as classes (which wasn't the way I was taught in school), and to get the reference coding you need to specifically say that you want it, like this:

proc logistic..
class period(param=ref ref='basevalue');

Where you put in the value of the base value.  I'm not sure about how mixed does the reference coding, but perhaps that is the difference; it might not hurt to try it out.

-Mary

--- anwestover@SBCGLOBAL.NET wrote:

From: Arthur Westover <anwestover@SBCGLOBAL.NET>
To: SAS-L@LISTSERV.UGA.EDU
Subject:      proc mixed levels, one level missing
Date:         Wed, 23 Jun 2010 11:30:33 -0700

I am running a proc mixed procedure.  I have a variable 'period' that has 10 different values.  I have confirmed this using proc freq.

When I run proc mixed, I only have 9 levels for the variable 'period.'  The number of levels for the other variables appear to be correct.

When I try using proc logistic, and throw in 'period', there are 10 levels.  I don't know what the problem is.

Here is my proc mixed statement:

 PROC MIXED data= big2 order=data;
   CLASS period VarC VarD VarE VarF VarG VarH;
   MODEL sysbp= VarA VarB VarE VarH VarF VarI VarJ cpd
pilus
    VarC|VarG|period/ ddfm=kr(firstorder);
   repeated / type=ar(1) sub=VarD(VarC);
   lsmeans VarC VarE VarG VarF/ cl diff;

  lsmeans VarC*period*VarG / diff cl slice=(period VarC VarG);
  lsmeans VarC*VarG / diff cl slice=(VarC VarG);
  lsmeans VarC*period / diff cl slice=(VarC period);
  lsmeans VarG*period / diff cl slice=(VarG period);
  lsmeans period / cl diff;
 run;