R help - Sep 2014 - Propensity Score Matching with Restrictions (Matching package)

Dear listers,

I am using Jas Sekhon's Matching package to perform propensity score
matching and like it a lot so far.
Still though I wonder whether it is possible to impose restrictions on the
Matching. I've seen the restriction parameter, but I doubt this is what I
want (or I don't get how to use it more neatly).

Here's what I  do:
I used a pool several years of observations into one dataset and estimate a
propensity score
using a standard glm / probit approach. I then use the fitted values as
propensity scores and perform the
matching.

Here's what I would like to do (in addition):
restrict the matching in way that only allows for matches within the same year,
so that only propensity scores within the same year are considered for a
respective match. Note that I don't what to estimate the years separately.

Is there a way to do so?

best regards

matthias

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Matthias Bannert
KOF Swiss Economic Institute
Leonhardstrasse 21
8045 Z?rich
Switzerland