PROC SURVEYLOGISTIC - SAS 9.3 vs. SAS 9.4

[kiwiepi]

Hi everyone,

I wonder why the confidence intervals (variance estimates) are slightly different when I run the exact same proc surveylogistic syntax using SAS 9.4 and SAS 9.3.  For example:

proc surveylogistic data= abc varmethod= BRR;
weight WGT_FULL;
repweights bsw1-bsw500 / df =24;
class sex (ref= '1') / param = ref;
model SLP=sex;
run;

The confidence intervals are slightly wider when I used SAS 9.4.  Are there any differences between the two versions for this procedure?? I can't seem to find the information anywhere else.

Thanks!

[ballardw]

The most likely reason would be the refinement of algorithms in the coding of procedures between releases.

Secondary posibilities are a change from a 32-bit to 64-bit implementation.

[Reeza]

I would contact SAS Support with this, if you have concerns. It also depends on the differences, if their less than 0.0001 it's most likely precision issues more than anything else.