Re: st: Offset variable

[Richard Williams <richardwilliams.ndu@gmail.com>]

At 10:53 PM 12/8/2013, Stephen A. Crowder wrote:
> I am developing an ordinal logistic regression model examining a 
> factor with several levels on my dependent variable. That part is 
> straight forward enough but I have a main independent variable that 
> ide like to control for in the examination of all of the other 
> independent variables. My question is would I need to make this an 
> "offset variable" in my models? I've been looking through the 
> literature and there's no clear answer available.
>
> Sent from my iPhone

First off, if you have a new topic you should start a new thread 
rather than reply to an old post. Even if you change the topic the 
threading gets thrown off in the archives. Also the totally unrelated 
extraneous text from the old thread that you quoted is distracting.

I think you probably just want to include the variable as another 
independent variable. In Poisson and related models offset is 
sometimes used as an alternative to the exposure option, e.g. it 
provides a way of dealing with cases that have been at risk for 
differing amounts of time. I don't think I have ever seen an example 
that used offset in an ologit model. I'd be curious to know if there 
are situations in which it makes sense.

I don't know if the offer is still good, but 9 years ago Nick Cox 
said SJ would be interested in a paper that discussed the practical 
uses of offset with commands like ologit:

<http://www.stata.com/statalist/archive/2004-10/msg00002.html>http://www.stata.com/statalist/archive/2004-10/msg00002.html

If somebody did successfully take Nick up on his offer I'd like to 
know what the paper was.



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Richard Williams, Notre Dame Dept of Sociology
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