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Re: st: using foreach in regression models


From   Phil Schumm <pschumm@uchicago.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: using foreach in regression models
Date   Tue, 25 Oct 2011 06:07:36 -0500

On Oct 25, 2011, at 5:10 AM, Tim Evans wrote:
> With regards to factor variables - does this only work on numerical values - I've used your code (which incidentally worked fine - thanks for that) but had to generate a new variable for one of my string variables.


Yes, factor variable functionality is restricted to nonnegative integers.  Note, however, that if you have a string variable that is a factor (i.e., with a relatively small number of distinct categories), then it is more efficient to store this as a numeric variable with a corresponding value label.  That efficiency may not matter if your dataset is small, but there are other reasons to prefer numeric variables (e.g., certainly manipulations are easier).


> Why is using -logistic- a better idea than using -logit- with O/R option if they give the same output? 


No major reason, other than it saves you having to use the -or- option (you can always type -logit- after using -logistic- to get the raw coefficients, if necessary).  You are correct that the results are identical.


-- Phil


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