[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]
st: unhelpful error message when running xtmixed on Stata 9.2
I am running xtmixed with a 3-level design. I am looking for the
significance of cross-level effects, and also for significance of fixed
and random coefficients.
I am running this on Stata 9.2 (with all the latest updates). I read on
http://www.stata.com/help.cgi?whatsnew that this problem of "hessian
becoming unstable and/or assymmetric" has been overcome in the latest
However, with ML (and reml), the program ends and it does provide me the
output. However, there are two warning messages in red. The first is,
"Hessian has become unstable or asymmetric". And, the second is, "Warning:
convergence not achieved; estimates are based on iterated EM".
What do I conclude with this. Is there any ill-conditioning of the data?
Or, is this bug in Stata?
Any advice will be greatly appreciated.
Be a PS3 game guru.
Get your game face on with the latest PS3 news and previews at Yahoo! Games.
* For searches and help try: