st: Pretreatment pair matching

[Wojciech Hardy <whardygildia@gmail.com>]

Hello all,
I'm trying to conduct a pair matching procedure only without having
the treatment group and control group set beforehand.

In fact we intend to use the pair matching to help us decide which
items should go to the treatment group (i.e. we'd like to find
'twins', and then put one of them into the treatment group, and the
keep other one in the control group, thus increasing the efficiency of
later statystical analysis).

I've found some commands allowing for measuring the treatment effect,
by comparing twins, but these do not apply to my case and
unfortunately I don't have the skills to modify the commands to give
me what I need.

What I'd want is to match the observations into pairs (generate some
"pair ID" probably), based on specified variables, without doing
anything else.

I thought of solving this by duplicating the dataset, giving the new
copy a "1" value in a treatment variable, and making the already
created commands match between the two identical groups. I'd have to
make it not match the observations with the same ID however (i.e. with
their own copies), and I don't know how to do it. Also, I'm not sure
if these commands report what pairs they've made in the process.

I haven't found any solution to this on the net, so I'll be really
grateful for any help!

Thanks indeed,
Wojtek Hardy
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