You should write a short do file where you keep one metro area at a
time, do psmatch2, save the outcomes and the generated counterfactual,
compute the overall ATT/ATE/ATU by hand as the mean difference once you
have looped over all metro area, and then finally bootstrap the standard
error(s).
Dann
****************************************************
Daniel L. Millimet, Associate Professor
Department of Economics
Box 0496
SMU
Dallas, TX USA
phone: 214.768.3269
fax: 214.768.1821
web: http://faculty.smu.edu/millimet
****************************************************
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Hui-shien
Tsao
Sent: Friday, April 07, 2006 11:41 AM
To: [email protected]
Subject: st: psmatch2 and matching within the metropolitan area
Hi all ---
     I am using psmatch2 to conduct propensity score matching.  My data 
is a pool of cases from four metropolitan areas.  I would like to match 
the treated tracts to the untreated tracts within the same metropolitan 
area.  I have tried to create dummy variables to control for 
metropolitan areas.  However, some of the matches still pick tracts from
a different metropolitan area.  Is there any way I can match within the 
same metropolitan area?  Thank you for your help in advance.
Hui-shien
*****
Here is my syntax:
gen random=uniform()
sort random
psmatch2 treat metro1 metro2 metro3 var1 var2 var3 var4, logit 
neighbor(1) common trim(3)
A simplified data structure:
id	metro	treat	Var1	Var2	Var3
1	1	1	1	4	4
2	1	0	2	1	3
3	1	0	3	1	1
4	1	0	3	5	2
5	1	1	2	3	5
6	2	0	1	1	3
7	2	0	1	2	8
8	2	0	2	5	6
9	2	0	3	3	3
10	2	1	3	7	1
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