-findit logit interaction- brings up two fairly recent Stata Journal
articles:
SJ-5-1 st0081 Visualizing main effects & interactions for binary logit
mod.
. . . . . . . . . . . . . . . . . . . . . . M. N. Mitchell and X.
Chen
(help vibl, viblicc, viblidb, vibligraph, viblmcc, viblmdb,
viblmgraph if installed)
Q1/05 SJ 5(1):64--82
presents new package vibl as visualization tool for
interpreting main effects and interactions in logit models
when using predicted probabilities
SJ-4-2 st0063 Interaction effects & standard errors in logit & probit
models
(help inteff if installed) . . . . . E. C. Norton, H. Wang, and C.
Ai
Q2/04 SJ 4(2):154--167
computes the marginal effect of a change in two interacted
variables for a logit or probit model, provides standard
errors, and graphs the interaction effect
The Mitchell and Chen paper and movies(!) demonstrating the commands are
available at
http://www.ats.ucla.edu/stat/stata/seminars/stata_vibl/viblm.htm
Hope this helps,
Scott
> -----Original Message-----
> From: [email protected] [mailto:owner-
> [email protected]] On Behalf Of Ashwin Ananthakrishnan
> Sent: Wednesday, July 20, 2005 4:57 PM
> To: [email protected]
> Cc: [email protected]
> Subject: st: Interaction terms in logistic regression using dummy
> variables
>
> Hi,
>
> I'm having some trouble interpreting the interaction
> terms in logistic regression using stata.
>
> My two variables of interest are gender (0-male,
> 1-female), and age categories (0- 65-69, 1-70-74,
> 2-75-79, 4-80 and above), and my outcome variable is
> anyscreen.
> When i type in the command,
> xi: logistic anyscreen i.gender*i.income, I get the
> following terms
> -Igender_1, _Iagecat_1, _Iagecat_2, _Iagecat_3,
> _IgenXage_~1,_IgenXage_~2, _IgenXage_~3.
>
> What do teh odds ratios for each of these terms mean -
> especially the interaction terms. And how do I test
> the significance of these interaction terms.
>
> Thanks,
> Ashwin
>
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