Key Concepts About Differences Between SUDAAN and SAS Survey
Procedures Logistic Regression Output
If you ran both the SAS Survey and
SUDAAN programs (or reviewed the output provided on the
Sample Code and Datasets Page
page), you may have noticed slight differences in the output. These
differences can be caused by missing data in any paired PSU or how
each software program handles degrees of freedom.
- Both programs calculate that 1,304 respondents have
hypertension and 2,515 do not.
- The beta coefficient and odds ratio estimates are
- The variance estimates and standard errors are identical
if there are no missing data in any paired PSUs (which was
the case in this example). They will be different if any one
of the paired PSUs contains missing data, as SAS and SUDAAN
handle stratum contribution from the missing cells
- The confidence intervals are slightly different since SAS
and SUDAAN handles degrees of freedom differently.