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Re: st: xmelogit error message


From   rgutierrez@stata.com (Roberto G. Gutierrez, StataCorp)
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: xmelogit error message
Date   Tue, 04 Mar 2008 17:02:47 -0600

Amanda Elam <amanda.elam@yahoo.com> asks:

> Does anyone have any idea what this error message means? Is there a
> work-around?

> . xtmelogit suboanw female || country: female, or variance
>  Refining starting values: 
>  initial values not feasible
>  r(1400);

The error message means that -xtmelogit-'s automatic choice of starting values
produced values that choked the optimizer.  Although rare, it has been known
to happen.

One solution would be to fit a simpler -xtmelogit- model

   . xtmelogit suboanw female || country:

and then use these estimates as starting values for the model you are
interested in

   . mat b = e(b)
   . xtmelogit suboanw female || country: female, or variance from(b)

-from(b)- sets the starting values as those from the simpler model, and
-xtmelogit- is smart enough to fill in a trailing zero as the starting value
for the log of the new variance component.

If that doesn't work, you could also try adding a further option to eliminate
the initial rough optimization process

    . xtmelogit suboanw female || country: female, or variance from(b) 
                refineopts(iterate(0))

(all on one line)

If that doesn't do the trick, then it would probably be best if we could get a
look at these particular data.  Amanda can feel free to email me directly or
tech-support@stata.com.

--Bobby
rgutierrez@stata.com
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