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Re: st: Pmatch2 and random


From   "Gauri Khanna" <[email protected]>
To   [email protected]
Subject   Re: st: Pmatch2 and random
Date   Fri, 13 Apr 2007 15:34:28 +0000

Dear Steven,

Thank you for responding to my question. I will then continue with my work as is.

Have a nice weekend.

Sincerely,

Gauri



From: Steven Samuels <[email protected]>
Reply-To: [email protected]
To: [email protected]
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
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