RE: st: analysis on PSM matched control group

["Sara Abrams" <sabrams@cgr.org>]

Thank you, Neha.  I don't think _treated is the variable I'm looking for
though.  

When I run the frequency of _treated for one of my PSM matches, I have
1,258 Untreated observations and 16 Treated observations.  I am looking
for a variable (or some combination of varaibles) that will identify
only those Untreated cases used as control matches to the Treatment
group.  In this case, I'm doing a 1:3 match, so I would expect about 48
cases, but probably less since there is some degree of replacement. 

-Sara



-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Neha Nanda
Sent: Monday, August 02, 2010 2:41 PM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: analysis on PSM matched control group

Hi Sara 

When you use psmatch2, several variables are created, one of them is
called _treated. You should see this variable through the data browser
once. It mentions treated or untreated for every treated or control
observation on or off the common support. 

I guess this should enable you to identify the control observations. 

Hope this helps. 

Neha Nanda 
Ph.D Candidate 
Florida State University 
Tallahassee
Fl-32304



----- Original Message -----
From: Sara Abrams <sabrams@cgr.org>
Date: Monday, August 2, 2010 11:29 am
Subject: st: analysis on PSM matched control groupS
To: statalist@hsphsun2.harvard.edu

> I've conducted some PSM analysis using the psmatch2 procedure (1:3
> nearest neightbor matching, logit model).  I need to run 
> frequencies and
> crosstabs for covariates used in matching by my outcome variable for
> both the unmatched and matched control groups.  How do you identify 
> thematched controls in the dataset after PSM in order to conduct 
> analysiswith just this susbset of cases?  How do you handle matched 
> cases that
> have been matched with more that one treatment case (with 
> replacement)? 
> 
> Thanks,
> 
> -Sara
> 
> 
>       
> 
> 
> 
> 
> 
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