Re: How do I perform generalized estimating equation for clustered data in SPSS?

Posted by Anh Nguyen on
URL: http://spssx-discussion.165.s1.nabble.com/How-do-I-perform-generalized-estimating-equation-for-clustered-data-in-SPSS-tp5740704p5740706.html

Hi Andy,

Thank you very much for your suggestion. You are truly my lifesaver :D

- so I tried both 2 models (Model 1- without interaction term; Model 2- with interaction term) as you suggested. And the coefficients of the key independent (intervention_control group) var change.

+The first model gives me a coef of 1.290.
+The 2nd model gives me  0.978

I think that the difference is normal because in model 2 I add one more variable to explain the variance of the post-test score. However, how I can figure out which model is better?

+ In case I should use model 2. How to interpret the interaction term? lets say the coef of Intervention * country 1 = 1.5 (p<0.05). How should I interpret it?

+ In case I should use model 1 and I want to get the impact of the intervention in each country, what if I split the file by country and get the coef of each country from there? Does it sound good to you?

P/S: 2 silly questions:
(1) what is the actual role of the Subject and within subject in the "Repeated" section in GEE? What if I entered individual ID variable instead of school ID variable?
(2) GEE model itself automatically controls for cluster effect (by selecting "robust estimator"), is it correct? If it's correct, why we need to enter "school" as a repeated subject?

I am very new to GEE and there is a lot of confusion for me. Your answer will help me a lot,

Thanks a million,