I have matched data via full matching, and I want to analyze the data
in Stata. I know I need to use a regression weight becuase I have
subclasses, but which one is the appropriate one?
Specifically, Stata offers three potential choices: pweights,
aweights, and iweights
For the record, I get the same results with "a" and "i". The "p"
weight slightly alters the results (becuase it switches over to robust
standard errors).
Also, I setx/estsimp in Clarify will not take "i" and "p" weight
estimates. In these cases Clarify will estimate and aggregate the
model results, but it will not calculate predicted probabilities or
expected values. Clarify has no problem with "a" weights.
Thanks!
--
Casey A. Klofstad
University of Miami
Department of Political Science
Coral Gables, FL
klofstad(a)gmail.com
http://moya.bus.miami.edu/~cklofstad
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I'm wondering whether I am ready to proceed to analysis:
(1) I ran optimal matching. The original N was 1044. The matched N =
996 (498 treated and 498 control).
(2) I took a "naive" approach by putting all of the 109 pre-treatment
variables I had on hand into the matching model. A handful of the
variables I dumped in have a standardized difference > .2 in the
matched data set (x = 8), but this is better than in the original data
(x = 12).
(3) One additional thing I did notice is that the distance measure is
not very well matched (std. diff. = .8), but it is improved from the
unmated data set (std. diff = 1.0).
Thanks,
-c
--
Casey A. Klofstad
University of Miami
Department of Political Science
Coral Gables, FL
klofstad(a)gmail.com
http://moya.bus.miami.edu/~cklofstad
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Hey all-
I have the fortune of having around 40 pre-treatment variables that I
can match on. Should I use them all?
If not, is there a systematic way to choose which variables to
include? For example, should I just use the ones that correlate the
most with the treatment and the outcome?
Thanks!
--
Casey A. Klofstad
University of Miami
Department of Political Science
Coral Gables, FL
klofstad(a)gmail.com
http://moya.bus.miami.edu/~cklofstad
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