st: Difference-in-Differences and Panel Data - In search of an adequate regression

[Barbara Engels <engels.ba@gmail.com>]

Dear Stata people,

I am currently working on a difference-in-differences model in its simplest form  - treatment and control group, pre- and post-intervention period. 
However, I got a large panel data set and I wonder what is the best way to estimate the DID in Stata to account for flaws like serial correlation. 
Should I go for a simple

reg y x  incl. interaction term, ROBUST

Or should I apply clustering?
Or even xtreg with fe? 

Any help is greatly appreciated.

Thanks a lot, happy 2013!

Barbara


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