Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
| From | "David Radwin" <dradwin@mprinc.com> |
| To | <statalist@hsphsun2.harvard.edu> |
| Subject | RE: st: RE: Moderation effect by splitting the sample |
| Date | Fri, 21 Dec 2012 09:02:24 -0800 (PST) |
Ebru, Again, I don't think this is necessarily the best approach for your situation, but amending Nick's code in http://www.stata.com/statalist/archive/2012-12/msg00758.html , it would be something like this: sysuse auto su weight, detail gen byte mysplit = cond(weight >= r(p75), 1, cond(weight <= r(p25), 0, .)) David -- David Radwin Senior Research Associate MPR Associates, Inc. 2150 Shattuck Ave., Suite 800 Berkeley, CA 94704 Phone: 510-849-4942 Fax: 510-849-0794 www.mprinc.com > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner- > statalist@hsphsun2.harvard.edu] On Behalf Of Ebru Ozturk > Sent: Friday, December 21, 2012 12:45 AM > To: statalist@hsphsun2.harvard.edu > Subject: RE: st: RE: Moderation effect by splitting the sample > > David, thank you. Can you also give the Stata commands for comparing upper > and lower quartiles? > > Kind regards > Ebru > > ---------------------------------------- > > From: dradwin@mprinc.com > > To: statalist@hsphsun2.harvard.edu > > Subject: st: RE: Moderation effect by splitting the sample > > Date: Thu, 20 Dec 2012 11:50:45 -0800 > > > > Ebru, > > > > I can't say for sure without knowing more about what you are trying to > do, > > but regarding splitting continuous variables, see this post and the > > references therein: > > > > http://www.stata.com/statalist/archive/2011-03/msg00154.html > > > > If you do split the variable anyway, consider comparing upper and lower > > terciles or quartiles (and not the upper and lower halves as a previous > > email intimated) to minimize loss of efficiency: > > > > Gelman, A., & Park, D. K. (2009). Splitting a predictor at the upper > > quarter or third and the lower quarter or third. The American > > Statistician, 63(1), 1-8. > > http://www.stat.columbia.edu/~gelman/research/published/thirds5.pdf > > > > David > > -- > > David Radwin > > Senior Research Associate > > MPR Associates, Inc. > > 2150 Shattuck Ave., Suite 800 > > Berkeley, CA 94704 > > Phone: 510-849-4942 > > Fax: 510-849-0794 > > > > www.mprinc.com > > > > > > > -----Original Message----- > > > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner- > > > statalist@hsphsun2.harvard.edu] On Behalf Of Ebru Ozturk > > > Sent: Thursday, December 20, 2012 11:42 AM > > > To: statalist@hsphsun2.harvard.edu > > > Subject: st: Moderation effect by splitting the sample > > > > > > > > > Dear All, > > > > > > For non-linear models, I want to test the moderation effect of X > > variable. > > > Can I test this moderation effect by spliting the sample according to > X > > > variable (moderator)? > > > > > > Kind regards > > > Ebru > > > > * > > * 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/ * * 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/