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Re: st: What should I do if stata can not show the result of nbreg
From
"Justina Fischer" <[email protected]>
To
[email protected]
Subject
Re: st: What should I do if stata can not show the result of nbreg
Date
Sun, 08 Jan 2012 16:32:10 +0100
Hi Yes Sun,
usually (from my experience), nbreg needs about 7 iterations to converge.
One reason for non-convergence could be
a high collinearity among variables.
So try with a more parsimonous model and find out which independent variable causes the problem.
Justina
-------- Original-Nachricht --------
> Datum: Sun, 8 Jan 2012 21:25:56 +0800
> Von: Ye SUN <[email protected]>
> An: [email protected]
> Betreff: Re: st: What should I do if stata can not show the result of nbreg
> Thanks for reminding.
> I use stata 11. My dependent variable is the number of boards that a
> director serves in.(Nboards) My test independent variable is the
> gender of the director, dummy variable (FD).
> So I want to run the following regression: nbreg Nboards FD (other
> control variables)
>
> I input the above command in stata, but it runs for hours and keeps
> showing
>
> Iteration 50: log likelihood = -58271.444 (backed up)
> numerical derivatives are approximate
> flat or discontinuous region encountered
> Iteration 51: log likelihood = -58271.444 (backed up)
> numerical derivatives are approximate
> flat or discontinuous region encountered
> Iteration 52: log likelihood = -58271.444 (backed up)
> numerical derivatives are approximate
> flat or discontinuous region encountered
> Iteration 53: log likelihood = -58271.444 (backed up)
>
> I want to know how to solve this problem if it still can not show the
> final results.
>
> I also want to know what is the difference between the command -nbreg-
> and -nbinreg-, please? It seems both of them are used for negative
> binomial regression.
>
> Thanks a lot
>
> SUN Ye
>
>
> On Sun, Jan 8, 2012 at 4:36 PM, Muhammad Anees <[email protected]>
> wrote:
> > A little picture of what you really did with -nbreg- will help us
> > understand your problem and also indicate what version of Stata is
> > used.
> >
> > On Sun, Jan 8, 2012 at 1:24 PM, Ye SUN <[email protected]> wrote:
> >> Dear all
> >> My dependent variable is count number: the number of boards that a
> >> director serves in (this kind of data seems not fit to poisson)
> >>
> >> I first try poisson regression and get the results and then I try
> >> -estat gof- to test whether there is overdispersion problem, it is
> >> insignificant indicating no overdispersion problem I think.
> >> I also try -zip- and get similar results, and vuong test indicates
> >> there is no excess zero problems I think.
> >>
> >> I also want to try negative binomial regression,( nbreg and zinb ),
> >> but stata run for quite a long time and still run without showing any
> >> results. What does that mean? Dose it mean that nbreg is inappropriate
> >> here?
> >>
> >> I want to ask, if -estat gof- after -poisson- shows the insignificant
> >> results, can I say this poisson model is OK and do not need to provide
> >> negative binomial regression results?
> >>
> >> Thanks for your help!
> >>
> >> SUN Ye
> >> *
> >> * 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/
> >
> >
> >
> > --
> >
> > Best
> > ---------------------------
> > Muhammad Anees
> > Assistant Professor/Programme Coordinator
> > COMSATS Institute of Information Technology
> > Attock 43600, Pakistan
> > http://www.aneconomist.com
> >
> > *
> > * 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/
--
Justina AV Fischer, PhD
COFIT Fellow
World Trade Institute
University of Bern
homepage: http://www.justinaavfischer.de/
e-mail: [email protected]. [email protected]
papers: http://ideas.repec.org/e/pfi55.html
*
* 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/