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From | <Seyi.Soremekun@lshtm.ac.uk> |
To | <statalist@hsphsun2.harvard.edu> |
Subject | Re: st: rate ratios from xtlogit using margins - how? |
Date | Fri, 17 Dec 2010 14:38:28 +0000 |
This is exactly what I wanted, checked against my hand calculations for rates and rate ratio and all are the same, plus couldn't figure out how to easily produce rate differences with CIs, which the dydx option with predict now solves - so many thanks. Seyi Dr Seyi Soremekun Department of Epidemiology and Public Health London School of Hygiene and Tropical Medicine London WC1E 7HT +442079272426 >>> Maarten buis 17/12/10 1:58 PM >>> --- On Fri, 17/12/10, SeyiLSHTM wrote: > I am running an xtlogit model (re) to compare stillbirth > rates in an intervention (=1) and a control group (=0) with > clustering. Stata outputs the odds ratio, though I'd rather > convert this to show the adjusted rates, and an adjusted rate > ratio or a rate difference (with CIs), as this is more > intuitive when presenting results to mixed audiences. The easiest way is probably to look at rates assuming that the random effect is 0, which is exactly the same as your manual computation. However, I would let -margins- do those computations, by specifying the -predict(pu0)- option, see: -help margins- and -help xtlogit postestimation-. You can also quite easily let -margins compute the rate difference for categorical variables, by using the -dydx()- option. *---------------- begin example ---------------- webuse union, clear xtlogit union age grade i.not_smsa south##c.year margins south, predict(pu0) margins, dydx(south) predict(pu0) *------------------ end example ---------------- (For more on examples I sent to the Statalist see: http://www.maartenbuis.nl/example_faq ) Hope this helps, Maarten -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * 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/ * * 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/