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From | "JVerkuilen (Gmail)" <jvverkuilen@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: OLS assumptions not met: transformation, gls, or glm as solutions? |
Date | Tue, 18 Dec 2012 16:00:29 -0500 |
On Tue, Dec 18, 2012 at 1:24 PM, Laura R. <laura.roh@googlemail.com> wrote: > Thank you very much for your support. > > I thought generalized linear models (this is what I meant with glm) > support different distributions of the dependent variable y, not the > residuals. My dependent variable and the residuals are both right > skewed, so maybe glm with inverse gaussian would be good. You're right, it's about the distribution of the dependent variable and as Maarten said, only in the linear model (Gaussian GLM) is it the case that the residuals line up so neatly with the dependent variable. An IG or gamma GLM usually has a log link, so it's going to deskew that way. One way to deal with the inferential uncertainty induced by model choice is to try it a few different ways to see if your substantive interpretation is sensitive to choice of specification. But that can lead to a real rabbit hole of decisions, too. I second Maarten's point about the fact that you're at the point that your own substantive needs and knowledge are necessary. * * 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/