Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
| From | "Hardy, Dale S" <Dale.S.Hardy@uth.tmc.edu> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | st: RE: RE: RE: AW: interactions for xtmelogit models |
| Date | Mon, 22 Feb 2010 11:32:47 -0600 |
My reservations are from basic principles I learned in logistic regression class...that the models with interaction terms must be hierarchically well-formed to give correct estimates. Both the single term (age) and the interaction term with age must be in the model. Is it different with xtmelogit models? And why? I just want to clarify this before I run the model. Thanking you in advance. Dale Hardy, PhD RD CDE CHES Research Associate University of Texas School of Public Health Houston, TX 77030 Phone: (713) 500-9221 Fax: (713) 500-9264 Email: dale.s.hardy@uth.tmc.edu ________________________________________ From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss [martin.weiss1@gmx.de] Sent: Monday, February 22, 2010 11:14 AM To: statalist@hsphsun2.harvard.edu Subject: st: RE: RE: AW: interactions for xtmelogit models <> " Why isn't age not in the model? Age is with the interaction terms but not as a single term. Would that make the model not hierarchally well-formed? " The answer is probably that the intention is "... to test against a model with no gender interactions, fixed or random", as stated at the bottom of page 14 of http://www.stata.com/meeting/fnasug08/gutierrez.pdf. So the focus is on interactions, not the main effect. HTH Martin -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Hardy, Dale S Sent: Montag, 22. Februar 2010 17:59 To: statalist@hsphsun2.harvard.edu Subject: st: RE: AW: interactions for xtmelogit models Hi Martin, A few months age I asked you a question about xemelogit interaction and you send me the link below. On page 15/36 of the presentation by Gutierrez entitled, ‘Tricks of the trade: getting the most out of xtmixed’, is a model for xtmixed interaction. My question is: Why isn't age not in the model? Age is with the interaction terms but not as a single term. Would that make the model not hierarchally well-formed? Thanks in advance for clarifying this issue. I look forward to hearing from you. Dale Dale Hardy, PhD RD CDE CHES Research Associate University of Texas School of Public Health Houston, TX 77030 Phone: (713) 500-9221 Fax: (713) 500-9264 Email: dale.s.hardy@uth.tmc.edu ________________________________________ From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss [martin.weiss1@gmx.de] Sent: Friday, October 16, 2009 9:38 AM To: statalist@hsphsun2.harvard.edu Subject: st: AW: interactions for xtmelogit models <> Note, for instance, the heavy use of interaction terms in http://www.stata.com/meeting/fnasug08/gutierrez.pdf, slide 15. The presentation is about -xtmixed-, but it may still help you approach your problem. Also see http://www.stata.com/meeting/2sweden/gutierrez_sweden07.pdf for -xtmelogit- HTH Martin -----Ursprüngliche Nachricht----- Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Hardy, Dale S Gesendet: Freitag, 16. Oktober 2009 16:17 An: statalist@hsphsun2.harvard.edu Betreff: st: interactions for xtmelogit models Hi All, I am looking at examples of xtmelogit models. I did not see any interaction terms used or any mentioned that interaction terms is recommended for use in these models. Have any of you who use this method used interaction terms in your modeling? How do you interpret the exposure variable with the interaction term/s and the addition of mixed effects variables/s? Any help is appreciated. Thanks. Dale Dale Hardy, PhD RD CDE CHES Research Associate University of Texas School of Public Health Houston, TX 77030 Phone: (713) 500-9221 Fax: (713) 500-9264 Email: dale.s.hardy@uth.tmc.edu * * 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/ * * 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/ * * 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/