Hi!
I've got suggestions:
1. Try to estimate the propensity score firstly (with a probit or logit) and set the prediction in the option p(your_prediction). This saves you time when running the command several times.
2. Specify the option "noreplacement" which yields a 1-1 matching as wanted.
JM.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of moleps islon
Sent: Martes, 10 de Noviembre de 2009 03:28 p.m.
To: [email protected]
Subject: st: psmatch2 and stcox
I´m trying to match 336 exposed patients from a cohort with a total of
966 patients using psmatch2:
xi:psmatch2 E `var', outcome(out) neighbor(1) common
I thought this would give me 1:1 matching, but I get 336 exposed and
662 control patients.
Then doing
ttest -different variables-, by(_t)
doesnt really match very well despite reasonable overlapping propensity distributions. Is this due to omitting the weighting option?
I´d like to use these propensity matched data for a logrank test, but I´m uncertain to the type of weight I should use. I assumed it should be pweight, but I found another posting here where they said fweight leaving me uncertain....
Regards
M
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