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From | "Qian, Yiming" <yiming-qian@uiowa.edu> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | st: RE: RE: using estimate store + suest+test to compare regression coefficients between two samples, how to adjust for clustering |
Date | Mon, 1 Mar 2010 22:20:52 -0600 |
Martin, Thank you very much for your kind help! It answers my question perfectly! I have a follow-up question: can I use similar tests for median regressions (qreg)? If not suest+test, how to compare coefficients across models for median regressions? I tried the following codes: qreg y x1 x2 x3 x4 if female==0 estimates store male qreg y x1 x2 x3 x4 if female==1 estimates store male suest male female I got the following error message: "unable to generate scores for model male suest requires that predict allow the score option r(322);" Thanks a lot! Yiming -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss Sent: Monday, March 01, 2010 2:51 PM To: statalist@hsphsun2.harvard.edu Subject: st: RE: using estimate store + suest+test to compare regression coefficients between two samples, how to adjust for clustering <> "The error message is: "male was estimated with cluster(family). re-estimate without the cluster() option, and specify the cluster() option with suest. r(322);"" Just follow Stata`s advice, I would say: ******* sysuse auto, clear reg price weight length if foreign est store for reg price weight length if !foreign est store dom suest for dom, cluster(rep) test ([for_mean]_b[weight ] = [dom_mean]_b[weight ]) ([for_mean]_b[length ] = [dom_mean]_b[length ]) testnl ([for_mean]_b[weight ] / [dom_mean]_b[weight ]) = ([for_mean]_b[length ] /[dom_mean]_b[length ]) ******* HTH Martin -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Qian, Yiming Sent: Montag, 1. März 2010 21:40 To: statalist@hsphsun2.harvard.edu Subject: st: using estimate store + suest+test to compare regression coefficients between two samples, how to adjust for clustering Dear Statalist, I use "estimates store + suest + test" to compare regression coefficients between two samples. It works fine until I tried to adjust clustering in the regressions. Below are detailed description of the problem. Is there a way to can get around this problem using "suest" or some alternative commands? I ran the same regression for two groups (male vs. female): Y = a1*x1 + a2*x2 + a3*x3 + .... I want to test: 1. The joint hypothesis that a1 and a2 are the same b/w the two groups. 2. The hypothesis that a1/a2 is the same b/w the two groups. The following stata codes work fine: reg y x1 x2 x3 x4 if female==0 estimates store male reg y x1 x2 x3 x4 if female==1 estimates store male suest male female test ([male_mean]_b[x1] = [female_mean]_b[x1]) ([male_mean]_b[x2] = [female_mean]_b[x2]) testnl [male_mean]_b[x1]/[male_mean]_b[x2] = [female_mean]_b[x1]/[female_mean]_b[x2]) However, if I add cluster() to the two regressions, I got error messages. reg y x1 x2 x3 x4 if female==0, cluster(family) estimates store male reg y x1 x2 x3 x4 if female==1, cluster(family) estimates store male suest male female The error message is: "male was estimated with cluster(family). re-estimate without the cluster() option, and specify the cluster() option with suest. r(322);" Thank you very much! Yiming Qian * * 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/