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re: st: PSMATCH with 2 conditions
From
"Ariel Linden, DrPH" <[email protected]>
To
<[email protected]>
Subject
re: st: PSMATCH with 2 conditions
Date
Wed, 8 Sep 2010 06:50:50 -0700
I would suggest another path to take here. cem (Coarsened Exact Matching)is
user written program by Gary King (http://gking.harvard.edu/cem/) that
allows you to force a match on a specific level of a variable (for example,
force gender to be exact). In this case, I would match some variables within
calipers and require exact matches where necessary on other variables.
I hope this helps
Ariel
Date: Tue, 7 Sep 2010 11:07:37 -0700
From: "Caskey, Judson" <[email protected]>
Subject: re: st: PSMATCH with 2 conditions
See the following post for an example of forcing a match:
http://www.stata.com/statalist/archive/2010-09/msg00073.html
In your case, say you have a 4-digit industry code (e.g. SIC). You can first
compute propensity scores, then make a new variable pscore2 that looks like:
pscore2 = year*100000+industry*10+pscore
If you have year 1999, industry 1234 and p-score 0.25, you get:
pscore2 = 199912340.25
If you put a caliper of, say, 0.5, it is impossible to match to a firm in a
different industry/year.
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