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| From | "David Roodman (droodman@cgdev.org)" <DRoodman@cgdev.org> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | RE: st: which -cmp- option to use for poisson model with count data? |
| Date | Mon, 30 Apr 2012 02:55:21 +0000 |
Laura, I'm afraid cmp is probably not appropriate. Unless the counts are high, count data can't be realistically modeled as the outcome of a single underlying process consisting of a linear functional plus a normally distributed error. The truncated regression model is intended for the same kinds of outcomes as Stata's truncreg command--one's with a continuous but truncated outcome. --David ------------------ From "Laura R." <laura.roh@googlemail.com> To statalist@hsphsun2.harvard.edu Subject st: which -cmp- option to use for poisson model with count data? Date Fri, 27 Apr 2012 20:16:46 +0200 Dear Stata users Can -cmp- be used with count data, which would normally be estimated using -poisson- in Stata? For example, the number of experts, ranging from 0 to 5 in the data (but theoretically limited to >0) . As this variable would be truncated (at 0, right truncated), I suppose I should use the option -indicator($cmp_trunc)- when using -cmp-? For example *---------------------------- Stata example begin--------------------- cmp (experts=x1 x2 x3, trunc(0 .)), indicators($cmp_trunc) *------------------------- Stata example end------------------------ would this be correct? Thank you very much for your consideration. Laura * * 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/