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Re: st: identifying comparison groups with similar distributions along one metric


From   Jeph Herrin <junk@spandrel.net>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: identifying comparison groups with similar distributions along one metric
Date   Tue, 20 Oct 2009 12:07:25 -0400


How about sort on cost, and then for each 4
values, assign randomly into groups? Eg,

 sort cost
 gen strata = mod(_n,4)
 gen random = uniform()
 bys strata (random) : gen byte group=_n

where I've been generous with code for clarity.

hth,
Jeph




Kate Rohrbaugh wrote:
This is my first posting to Statalist, so I ask for forgiveness in
any breaks in protocol.

I have a dataset of about 300 observations and I am going to separate
them into 4 groups -- not totally equal in size but based on certain
characteristics.  I want the four groups to all have similar
distributions along a certain metric (i.e., cost) -- so the mean,
median, SD, etc., are similar, so I want to sample observations from
each group.  I'll choose one of the four groups as my baseline
(probably the one with smallest range or the fewest number of
observations - but I'm open to any suggestions about that as well).


What's the best approach for doing this?  I suspect this question has
been addressed numerous times in various places, so being pointed in
the right direction is sufficient.  Note: we still have Stata 9.2, so
nothing too fancy.

Thank you!

Kate

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