st: does -margins- work after -menbreg- or -mepoisson- in Stata 13?

[Steve <drlead@prodigy.net.mx>]

I'm trying to use -margins- after -menbreg-.

No matter how I set up the -margins- command, I receive the following 
error message:

default prediction is a function of possibly stochastic quantities other 
than
e(b)
r(498);

Here's just one example of the syntax I've used:
     margins x1, at(x2=(-1(.1)3))
where
    x1 = dichotomous variable
and
    x2 =  continuous variable

Both variables are in the -menbreg- model.

I have the same problem after mepoisson.

I know that -margins- works after -mixed- in Stata 12.

Am I neglecting something or will -margins- not work after -menbreg- and 
-mepoisson- in Stata 13?  Are there other new mixed commands in Stata 13 
after which -margins- will not work?

Steve Rothenberg
Instituto Nacional de Salud Pública
Cuernavaca, Morelos, México


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