st: Comparison of Coefficients in Conditional Logistic regression

["A. Karvounidis" <A.Karvounidis@uvt.nl>]

Dear Statalist subscribers,
My name is Anestis Karvounidis and I would like to pose a question regarding the comparison of the results of conditional logistic regression. I want to check for the moderatoring effect of type of business activity (if the company has manufacture or service activity in host country) in distance factors (Culture, geographic, economic). Given that the model was non convergent when I was including the interaction variables, I forced to run three times the same regression (Conditional logistic regression) with the same variables but with part of the initial sample. More specifically, the first model has the total sample, while the rest two models have the one only the part of sample with manufacture activity and the other the part with service activities. 
My point is to check if the type of business activity moderated or intensify distance effect. As a result I want to compare the coefficients of these 3 models. Can I do it directly that, or should I do any additional test. I found suest order of STATA but it does not work, probably because I have different size of sample. Should I prove that the change is statisticaly significant? How can I do it that?

Thank you very much for your help.

Kind regards,
Anestis Karvounidis 



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