st: testing for differences in parameters with clogit with standardized parameter estimates

[Karin <twentestat@yahoo.com>]

Dear Stata-users,

I have a question on the following: 
I have data on two conjoint studies with the same design (i.e. same attributes, 
same levels). I analysed the studies seperately with clogit.
Next I analysed the data simultanuously in order to test whether the parameter 
estimates for the attributes are different or not between the two samplegroups. 
For this I made interaction terms for each attribute and the samplegroup. 
This was indeed the case, the parameters for the two sample differ. 

Now I want to test whether the efficiency (in terms of standard errors of the 
estimates e.g.) differs between the two samples. 

If and what is the appropriate test to do so? How can I do this in stata? Can 
anyone give me a hint to look for this?

Thanks in advance,

Karin
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