Please recommend reading materials about categorical variables in logistic regression.

[Lychee]

Thank you!

[INGODWETRUST]

Do you want a material specifically only for categorical variables? or a material on logistic regression?

Either way, I'd suggest a book called " Statistics for Business by authors: Anderson, Sweeney and Williams". A wonderful book indeed. Have fun

[Reeza]

If you're familiar with logistic regression and need the SAS details these are good references:

UCLA, their annotated output is useful though a bit out of date:

SAS Topics: Logistic

And of course the documentation:

Example 51.2 Logistic Modeling with Categorical Predictors

SAS/STAT(R) 9.2 User's Guide, Second Edition

Read up on the class statement and how it dummy code/effect code variables as this is a common source of errors.

FAQ: What is effect coding?

FAQ: What is dummy coding?

Search logistic regression on lexjansen.com for many relevant papers.

My biggest suggestion is to find a set of data/analysis and figure out how to replicate it in SAS before doing your actual analysis on your data. It will save you many mistakes.