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From |
Ashish Gupta <ashishatbhu@gmail.com> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: Interaction term in logistic regression |

Date |
Tue, 22 Apr 2014 13:54:48 +0530 |

Thanks Martin I have mistakenly placed dependent variable after the independent variable.In addition,i would like to inquire whether I can use spline models for separate age groups( binary 1/0 for each age-group).Since I am looking for the odds of mortality across age groups. Best regards Ashish Kumar Gupta Senior Research Fellow (Population Studies) International Institute for Population Sciences (IIPS), Govandi Station Road, Deonar, Mumbai-400 088, INDIA Mobile No.: +91 9967106908 On Tue, Apr 22, 2014 at 12:50 PM, Maarten Buis <maartenlbuis@gmail.com> wrote: > I can see a couple of problems: > > 1) For a logistic regression the dependent variable needs to be the > first variable mentioned in the variable list and it should not > contain a prefix (i.). > > 2) The -xi:- prefix is outdated, you should use the factor variable > notation instead whenever possible, see -help fvvarlist-. > > 3) I would consider using a linear spline (1st order spline) instead > of age in categories (0th order spline). The linear spline is a more > flexible than age categories, but is still easily interpretable. For > even more flexible but still interpretable effects you can look at: > Roger B. Newson (2012) "Sensible parameters for univariate and > multivariate splines" The Stata Journal, 12(3): 479-504. > > 4) If you use income as a variable, then I would call it income and > not economic status. The latter could be interpreted as more general, > for example it could wealth, which you did not do in your model. > > -- Maarten > > > On Tue, Apr 22, 2014 at 7:12 AM, Ashish Gupta <ashishatbhu@gmail.com> wrote: >> I am planning to employ logistic regression with interactions to see >> the effect of socio-economic characteristics on age-specific >> mortality.I would like to know that how one can include interaction >> term (Age versus economic status) in adjusted as well as unadjusted >> model. >> Example of the model- >> xi : logit i. race i. age_group i. income i.place_res i.age_group ##i.income >> >> Any response will be appreciated. >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/faqs/resources/statalist-faq/ >> * http://www.ats.ucla.edu/stat/stata/ > > > > -- > --------------------------------- > Maarten L. Buis > WZB > Reichpietschufer 50 > 10785 Berlin > Germany > > http://www.maartenbuis.nl > --------------------------------- > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**References**:**st: Interaction term in logistic regression***From:*Ashish Gupta <ashishatbhu@gmail.com>

**Re: st: Interaction term in logistic regression***From:*Maarten Buis <maartenlbuis@gmail.com>

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