When doing Logistic regression in SAS there are several procedures that you can use:
- Proc Logistic
- Proc Genmod
- Proc Surveylogistic
- If you’re using survey weights then you need to use SurveyLogistic to have your variance and confidence intervals calculated appropriately.
- For categorical variables, use a CLASS statement and specify PARAM=REF to use referential coding. If you use EFFECT coding (the default option) then your p-values may not align with your odds ratio confidence intervals.
- Use the ODDSRATIO statement to get odds ratio for specific variables or to compare different levels.
- /EXPB after your model statement will allow you to have the ratios included in your output.
- Check the event selection that is modelled in SAS. By default SAS models the event Y=0, when you usually want Y=1. You can modify by specifying the event in your model statement.
So that are some quick heads up regarding using proc logistic in SAS.