Hi, again!
I am comparing optimal matching to two nearest neighbor matching methods.
I ran the PSM in MatchIt! and I am seeing some weird stuff in the
distributions of my covariates for the optimal method. The standardized
mean differences are very low on average for my simulation runs. However
the treated and control groups ore very dissimilar in the optimal matching
method. The covariate distributions in the nearest neighbor methods are
very similar. How can I explain that?
Thanks!
Shane Phillips
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I'm not sure I follow your question, especially the statements
"The standardized mean differences are very low on average for my simulation runs.
However the treated and control groups ore very dissimilar in the optimal matching method.
The covariate distributions in the nearest neighbor methods are very similar."
You may need to provide more background, unless someone else on the list can respond...
Liz
On 2/1/12 10:34 AM, "Shane Phillips" <phillips.shane(a)gmail.com> wrote:
Hi, again!
I am comparing optimal matching to two nearest neighbor matching methods. I ran the PSM
in MatchIt! and I am seeing some weird stuff in the distributions of my covariates for the
optimal method. The standardized mean differences are very low on average for my
simulation runs. However the treated and control groups ore very dissimilar in the
optimal matching method. The covariate distributions in the nearest neighbor methods are
very similar. How can I explain that?
Thanks!
Shane Phillips