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| From | Maarten Buis <maartenlbuis@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: Count data interaction terms |
| Date | Tue, 23 Aug 2011 12:12:54 +0200 |
On Tue, Aug 23, 2011 at 11:40 AM, DA Gibson <DAGibson1@sheffield.ac.uk> wrote: > Hi Maarten > > Thanks for that, i do have one further question however. In the > example the IRR on the c.persons#c.child interaction term is positive > at .77 however in your email you say that the interpretation is that > the effect is reduced. These effects are ratios rather than differences, so any number less than 1 is a "negative" effect. If you multiply some number with a number less than one, than the result will be smaller than the original number. You can transform ratios into percentage changes by doing (ratio - 1)*100%, i.e. multiplying the effect of persons by 0.77, is equivalent to saying that the effect of persons changes with -23% when the extra person is a child. 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/