Hi ,
I have come across some odd behaviour.
I am attempting to capture xtmixed in a simulation study. However it doesn't
seem to be working.
So i have :
capture noisily xtmixed obs_ht age_1 age_2 || id: age_1 age_2 ,
cov(unstruct)
it has trouble converging. And eventually gives the following error:
Hessian is not negative semidefinite
conformability error
But i am not sure why this is just not being skipped to the next run.
Any ideas or suggestions
I am running stata 12.1
Thanks
Adrian
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Adrian Sayers
RM 3.09
Medical Statistician
University of Bristol
School of Social and Community Medicine
Canynge Hall
39 Whatley Road
Bristol
BS8 2PS
United Kingdom
Tel +44 (0)117 9287258
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