From: Steven Samuels <ssamuels@albany.edu>
Reply-To: statalist@hsphsun2.harvard.edu
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Pmatch2 and random
Date: Fri, 13 Apr 2007 07:51:10 -0400
This is expected behavior. The fact that you randomly sorted the
observations doesn't change the fact that some have the same propensity
scores (often because the scores are based primarily on categorical
variables so that there are many ties).
On Apr 13, 2007, at 5:26 AM, Gauri Khanna wrote:
Dear Stata list,
I am running the psmtach2 command to estimate propensity scores. I use
Stata 9.2 and psmatch2 is updated.
While running this command, in my output I get a comment:
"There are observations with identical propensity score values.
The sort order of the data could affect your results.
Make sure that the sort order is random before calling psmatch2"
So I do the following
-gen random=uniform()
sort random-
but still get the same message
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
_________________________________________________________________
