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Re: st: Probabilities after logit?


From   sjsamuels@gmail.com
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Probabilities after logit?
Date   Mon, 1 Jun 2009 11:08:35 -0400

I agree with Paul.  Basically, the quantities that you are trying to
calculate are meaningless unless every other covariate has a
meaningful zero value _and_ the intercept is zero.

-Steve

On Mon, Jun 1, 2009 at 9:12 AM, E. Paul Wileyto <epw@mail.med.upenn.edu> wrote:
> Probabilities are calculated here given predictor values, and generating
> probabilities subject by subject is what makes sense.  What you are
> suggesting is only going to work well in very simple cases.
>
> It won't work at all for continuous predictors  If all of your predictors
> are binary, categorical, or ordinal, I'd still use predict, and then
> collapse across your predictor categories.  If you have 1 or 2 binary
> predictors, you could use nlcom, inserting predictor values into the
> equations.
>
> If
>
>
>
>
>
> Kanter, Rebecca wrote:
>>
>> Hi,
>>
>> I would like to get the logit output in stata in a form of "probabilities"
>> (via transforming the log odds through the formula e^x / (1 + e^x)). Does
>> anyone know if there is a command(s) to do this? (I know you can get the
>> "predicted" line in the probability format, but am looking here, to be able
>> to see the coefficients in the form of probabilities).
>>
>> Thanks,
>> Rebecca
>>
>> ___________________________________________
>> Rebecca M. Kanter
>> PhD Candidate
>> Johns Hopkins Bloomberg School of Public Health
>> Department of International Health
>> Center for Human Nutrition
>>
>> *
>> *   For searches and help try:
>> *   http://www.stata.com/help.cgi?search
>> *   http://www.stata.com/support/statalist/faq
>> *   http://www.ats.ucla.edu/stat/stata/
>>
>>
>
> --
> E. Paul Wileyto, Ph.D.
> Assistant Professor of Biostatistics
> Tobacco Use Research Center
> School of Medicine, U. of Pennsylvania
> 3535 Market Street, Suite 4100
> Philadelphia, PA  19104-3309
>
> 215-746-7147
> Fax: 215-746-7140
> epw@mail.med.upenn.edu
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

*
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