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Re: st: problem with the interpretation of pstest after psmatch2, t-tests and percentage of bias provide conflicting results, which one should I follow?
From
Adam Olszewski <[email protected]>
To
[email protected]
Subject
Re: st: problem with the interpretation of pstest after psmatch2, t-tests and percentage of bias provide conflicting results, which one should I follow?
Date
Sat, 12 Jan 2013 23:18:13 -0500
Hi Simone,
t-test based comparisons after PS matching are highly controversial.
t-test makes a lot of usually untenable assumptions (are the variables
normally distributed?), and moreover is too sensitive to sample size.
A non-significant test might just mean a small sample, while a
minuscule difference in means might be "significant" in a very large
sample.
Standardized differences of means seem to be more accepted, although
for continuous covariates comparing actual distributions may be most
persuasive.