Andy,
you will have to adjust your degrees of freedom to account for the fact
that some of them are duplicates. Match() or MatchIt() does it
automatically for you, so the easiest way is to rely on them when matching
with replacement. If you want to do it manually, take a look at the
MatchIt manual. I *think* they have a discussion of how this works
somewhere.
Holger
Hi...
When using Match and replace=T, multiple controls are matched to single
treatment observations in my data. And then, when taking the subset of
matched data for the parametric post-matching analysis, extracting it into
a
new object using $index.treat and $index.control, I end up with duplicate
treatment observations because of the replace=T matching procedure. Should
I
keep the duplicate observations for analysis or drop them? It would seem
strange to get rid of them since it's what enforces balance in the matched
data.
Thanks,
Andy
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Holger Lutz Kern
Graduate Student
Government Department
Cornell University
Graduate Associate
Harvard University
Institute for Quantitative Social Science
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