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Re: Re: st: Debugging estimation changes


From   Clyde B Schechter <clyde.schechter@einstein.yu.edu>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: Re: st: Debugging estimation changes
Date   Sat, 23 Jun 2012 14:23:38 +0000

Ed,

If there is no sampling going on in your code (even hidden within ado files that others wrote) another possible source of indeterminacy of results is -sort-.

If you -sort- your data on a varlist that does not uniquely identify the observations, the resulting sort order is indeterminate and Stata does not guarantee to produce the same results each time.  If anything from that point on depends on the sort order of the data, you will likely get different results with re-runs.

If this is the problem, you should change any -sort- statements so that either you include enough variables in the varlist to uniquely determine the sort order, or use the -,stable- option.  With that option, Stata will preserve the original order of the data within the -varlist- groups.

Hope this helps.

Clyde Schechter
Dept. of Family & Social Medicine
Albert Einstein College of Medicine
Bronx, NY, USA


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