st: Difference-in-Difference and matching using -diff

[James Bernard <jamesstatalist@gmail.com>]

Hi all,

the user-written command -diff seems like a panacea for all the
problems one may face in doing propensity score matching and
difference-in-difference. It is fairly simple to implement and there
are enough options to work with.

A good difference-in-difference analysis involves matching of the
control and treatment groups, so that they are very similar in every
possible way, except receiving the treatment. Matching is often done
via propensity score matching (-pscore) etc.

I would like to know if any of you have used this command. How
reliable is it? Can I truly say that I did propensity score matching
and then did difference-in-difference by just running diff and
supplying it with control variables.

Thanks,
James
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