st: psmatch2-identifying matched pairs

["Garth Rauscher" <garthr@uic.edu>]

I apologize if this has been answered before but I could not find the
solution in the archives. When I perform 1-1 matching using psmatch2,
several new variables are added to my dataset. Among these are _id, which is
a unique identifier for each observation, and _n1, which identifies the _id
for the observation in the matched pair. I?d like to be able to define a new
variable that uniquely identifies each matched pair. In other words if there
are 100 observations making 50 matched pairs, there are 100 unique values of
_id and 100 unique values of _n1. I?d like a variable with 50 unique values,
one for each matched pair. Stata doesn?t appear to create this variable.
Having this variable would enable me to conduct stratified analyses
(stratifying on matched pairs) outside of what is provided by psmatch2.
Given _id and _n1 there is probably a way to do this but it is beyond my
skill set.  I?d appreciate if there are any ideas out there as to how to go
about defining this variable.

Thanks very much

Garth

Garth Rauscher
Associate Professor of Epidemiology
Division of Epid/Bios (M/C 923)
UIC School of Public Health
1603 West Taylor Street
Chicago, IL 60612
ph: (312)413-4317
fx:  (312)996-0064
em: garthr@uic.edu
 



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