Dear Statalisters,
I am implementing an IV estimaiton. Compared to robust OLS estimation results, I found that
one INCLUDED variable changed from insignificant in robust OLS esitmation to significant in IV
estimation. But, from what I understand, IV esitmators are supposed to larger standard errors
than OLS estimators. If this is correct, the IV estimators are supposed to be less significant than
OLS estimators. I wonder why this happened. Is there anyone running into the same problem
and understanding it? Thank you very much!
Best regards,
Jian Zhang
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