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

[Maarten Buis <maartenlbuis@gmail.com>]

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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>
> *
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>



-- 
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------

*
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