Same expected values (i.e. model output): yes Same Betas: no *From:* gov2001-l-bounces at lists.fas.harvard.edu [mailto: gov2001-l-bounces at lists.fas.harvard.edu] *On Behalf Of *Patrick Lam *Sent:* 10 April 2007 23:17 *To:* gov2001-l at lists.fas.harvard.edu *Subject:* [gov2001-l] Question on Negative Binomial parameterization Hi all, I had a quick question on parameterization of the negative binomial. We have two ways of doing it, with the parameterization of sigmasq in Gary's notes and the parameterization of theta in Zelig. It seems to me that despite the different parameterizations and superficially different density functions, the betas and the expected values should be the same for both. Is that correct? I've written both log likelihood functions and unless I made a coding error, it seems I'm getting two very different sets of betas. The one I get following the Zelig parameterization matches the output from Zelig. Thanks Patrick -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 269.0.0/754 - Release Date: 09/04/2007 22:59 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 269.0.0/754 - Release Date: 09/04/2007 22:59 _______________________________________________ gov2001-l mailing list gov2001-l at lists.fas.harvard.edu http://lists.fas.harvard.edu/mailman/listinfo/gov2001-l