Two commands: Nomreg and Plum or GenLin. Spss has a tutorial on multinomial regression in tutorials->case studies -> regression options. A book: J. Scott Long, Regression models for categorical and limited dependent variables.
Your Former Student (FS) has a three category DV. After FS has been through crosstabs, start with Nomreg/Genlin, which computes a regression for each category against the reference category. The output will show an intercept and predictor slopes for each category. If the predictor slopes are all the ‘same’ across categories, FS can switch to Plum (where the same assumption can be explicitly tested, unlike GenLin where it can’t). The predictors have lots of categories and when looking for interactions the categories kind of explode. But, why not treat the IVs as just IVs rather than as factorial IVs? Therefore, compute the IV contrast terms (and contrast term interactions and enter them in the regressions (use the WITH keyword, not the BY keyword). Harder to interpret? Yes. But, FS won’t be faced with messages about cells with few or no cases.
Gene Maguin
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Dates, Brian
Sent: Wednesday, November 14, 2012 10:34 AM
To: [hidden email]
Subject: Analysis with Categorical Independent and Dependent Variables
I’ve had a question from a former student who has been asked, as a legislative aide, to analyze data from a legislative district. All variables are categorical. For example, he would like to know what the effect of Religion (Roman Catholic, Maronite, Chaldean, Melkite, Other), Gender (Male, Female), Education (Less than High School, High School, Some College, Completed College, Advanced Degree), and Age Group (18-25, 26-54, 55 or older) had on voting behavior (Obama, Romney, Other). Factorial logistic regression would be in order if the dependent variable was dichotomous, or at least that’s my understanding. But it’s not, and there will be other analyses in which the dependent will have more than three categories. Any ideas would be welcome. Thanks.
Brian G. Dates
Director of Evaluation and Research
Southwest Counseling Solutions
1700 Waterman
Detroit, MI 48209
313-841-7442
Leading the Way in Building a Healthy Community
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