st: re: proper use of if

[Christopher Baum <kit.baum@bc.edu>]

<>
Nick said

I agree that -if e(sample)- is a good piece of syntax to know, but otherwise I don't see a practical difference here. 

If the observations couldn't be included, the result will be missing and the consequence is the same.


Well, not quite so. If the dependent variable was missing but the RHS variables were not, -predict- could create a prediction for those observations.  Repeating the if condition would not catch that, but e(sample) would.

Kit

Kit Baum   |   Boston College Economics & DIW Berlin   |   http://ideas.repec.org/e/pba1.html
                              An Introduction to Stata Programming  |   http://www.stata-press.com/books/isp.html
   An Introduction to Modern Econometrics Using Stata  |   http://www.stata-press.com/books/imeus.html


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