Re: st: A simple question about R-squared

["David W. Harless" <dwharles@vcu.edu>]

Albert Newton wrote:
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Dear Stata users,
   Here is outputs of my ivreg and I found R-sqaured is just a dot.
Does anyone has anyidea what's going on with R-squared?  Why is it a
dot?  Thanks a lot.
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In all likelihood because the R-squared is negative.  Re-run -ivreg- without the -robust- 
option and you should see that the Model sum-of-squares is negative.  But this does not 
necessarily indicate a problem as the concept of R-squared is not well-suited to 
instrumental variable regression.  Also see, the FAQ "How can I get an R-squared value 
when a Stata command does not supply one?" at
http://www.stata.com/support/faqs/stat/rsquared.html

Dave Harless
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