Date:         Thu, 4 Nov 2004 12:14:34 -0500
Reply-To:     "DePuy, Venita" <depuy001@DCRI.DUKE.EDU>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "DePuy, Venita" <depuy001@DCRI.DUKE.EDU>
Subject:      Re: Proc Logistic Question
Comments: To: K Fernandes <kafernan@UWATERLOO.CA>
Content-Type: text/plain; charset="iso-8859-1"

 Hi Kim -
you might try running this with reference coding selected (I believe  that
you add /param=ref  after your model statement)
The difference might be as simple as different types of coding between R &
SAS (although I don't use R, so don't know) . . ie same information just
presented differently.

Other than that, the code looks fine to me (not to say I couldn't just be
oblivious)

HTH
Venita


-----Original Message-----
From: K Fernandes
To: SAS-L@LISTSERV.UGA.EDU
Sent: 11/4/2004 11:46 AM
Subject: Proc Logistic Question

Hello,

Suppose I have a dataset called Summary1 which is this:

Rand Sim_No Cen_Num x m y
1 1 1 0 1 0
1 1 1 1 4 0
1 1 2 0 3 1
1 1 2 1 4 2
1 1 3 0 5 1
1 1 3 1 4 2
1 2 1 0 2 1
1 2 1 1 1 1
1 2 2 0 1 0
1 2 2 1 3 0
1 2 3 0 3 3
1 2 3 1 3 2

(My actual dataset has more than one value in the Rand column (i.e. 1 to
5) and more than two values in the Sim_No column (i.e. 1-3).

I would like to run proc logistic to do two things:
1) see what the relationship is between x and y/m for each centre of
each simulation and randomization (i.e. for the data above, get 6
estimates of beta and put them in a table called BetaEsts)
2) see what the relationship is between x and Cen_num and y/m for each
centre of each simulation and randomization (i.e. again get 6 estimates
of beta and put them in a table called BetaEsts1)

For 1), I tried this:
proc logistic data = Summary1;
  model y/m = x ;
  ods output ParameterEstimates = BetaEsts;
  by Rand Sim_No;
run;

and for 2 I tried this:
proc logistic data = Summary1;
  model y/m = x Cen_Num;
  ods output ParameterEstimates = BetaEsts1;
  by Rand Sim_No;
run;

However, the estimates I get for 1) does not correspond to estimates I
get in R, so I think there is a problem with my statements.  Can anyone
spot it?

Thank you very much for your help,
Kim