Re: st: why does stata creates missing values when running zinb model

[Ekaterina Hertog <ekaterina.hertog@sociology.ox.ac.uk>]

Dear Maarten,
You are right, I have a big dataset of marriage customers which includes 
both men and women of ages up to 70.
Thank you very much. I experimented a bit and it seems Stata is just 
telling me how many observations it is not using in this particular model.
Ekaterina

On 19/10/2011 10:35, Maarten Buis wrote:
> Given that you used an if condition I assume that your dataset
> actually contains more observations than just women who are less than
> 40. If you type after your -zinb- model -count if !e(sample)-, do you
> get 31478? If that is the case than there is probably no problem. (In
> that case someone at StataCorp forgot a -quietly-.)
>
> -- Maarten
>
> On Wed, Oct 19, 2011 at 10:44 AM, Ekaterina Hertog
> <ekaterina.hertog@sociology.ox.ac.uk>  wrote:
> > Dear All,
> >
> > I am trying to run a zero inflated negative binominal model in Stata 11. My
> > dataset contains 13440 women below 39 who are marriage agency customers. The
> > customers of the agency HAVE to provide information on all the major
> > demographic variables so there are no missing values on key variables (age,
> > height, income, education etc). My dependent variable is nbidder which
> > stands for the number of offers a given customer received over the past
> > year. About 25% of women did not receive any offers (nbidder=0)
> >
> > The command I typed is:
> >
> > zinb nbidder prsexrat20441539 ciunmsexrat2039 guntotot age agesq bmi divwid
> > havechildren lninc university smoker if age<=39&  sex==2, nolog inf(age
> > agesq bmi havechildren lninc university) exposure(duration)
> >
> > prsexrat20441539 ciunmsexrat2039 are measures of local sex ratio for each
> > customer and guntotot measure how rural the area is.
> >
> > Once I run the command I get a message (31478 missing values generated). I
> > will be very grateful for any advice of why this may be happening,
> > Ekaterina
> >
> > On 19/10/2011 00:28, Nick Cox wrote:
> > > You fail to tell us anything whatsoever about your data (except that
> > > the number of observations presumably is at least 3000) and you do not
> > > tell us even the exact command you typed. This is quite contrary to
> > > all the advice given to you in the FAQ and in particular repeated on
> > > the list within the last 24 hours.
> > >
> > > -set trace on- will show you where what you think is a problem occurs.
> > > If the resulting log is long you may need to edit it for Statalist.
> > > Otherwise why not liaise with Stata technical support directly? As
> > > above, they will want to know about your dataset.
> > >
> > > Nick
> > >
> > > On Tue, Oct 18, 2011 at 11:20 PM, Ekaterina Hertog
> > > <ekaterina.hertog@sociology.ox.ac.uk>    wrote:
> > > > Dear All,
> > > > I am trying to run a zero inflated negative binominal zinb model in Stata
> > > > 11
> > > > and the first output Stata gives me is: 3000 missing values generated. I
> > > > am
> > > > not sure why this is happening and it sounds wrong, but I cannot find out
> > > > what exactly this means and hence how to solve the underlying problem.
> > > > Any
> > > > advice will be greatly appreciated,
> > > *
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> > *
> > *   For searches and help try:
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> > *   http://www.ats.ucla.edu/stat/stata/

*
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