st: comparing mixed-effects regression coefficients between models

["Eike Mark Rinke" <emrinke@web.de>]

Dear statalisters,

I would like to compare two coefficients for the same regressor between two multilevel mixed-effects linear models with different outcomes (but otherwise identical specification, and estimated on the same sample, with only minor differences between models due to missing values). However, I do not seem to find a way to accomplish this task, so I am turning to the list for advice.

The situation looks something like this in Stata:

xtmixed y1 a b || id: // model a
xtmixed y2 a b || id: // model b

Is there a way to test for the difference between the coefficients/partial correlations a --> y1 and a --> y2? In other words, is there a way to test if a is significantly more strongly/weakly associated with y1 than with y2? (Using -suest- with subsequent Wald testing does not seem to work in a mixed-effects setting; suest produces the following error upon an attempt to combine estimates for models a and b: >>unable to generate scores for model M19 suest requires that predict allow the score option<<)

I'll be grateful for any thoughts, suggestions, pointers or immediate solutions for this problem.

Eike

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