Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

R: st: Zero-truncated Negative Binomial convergence


From   "Carlo Lazzaro" <carlo.lazzaro@tiscalinet.it>
To   <statalist@hsphsun2.harvard.edu>
Subject   R: st: Zero-truncated Negative Binomial convergence
Date   Wed, 18 Mar 2009 07:24:10 +0100

Dear Tony,
thank you. 

Kind Regards,
Carlo

-----Messaggio originale-----
Da: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di Lachenbruch,
Peter
Inviato: martedì 17 marzo 2009 21.52
A: statalist@hsphsun2.harvard.edu
Oggetto: RE: st: Zero-truncated Negative Binomial convergence

152. 	Lachenbruch,  P. A., (2001) "Comparison of competitors to the two
part model" Statistics in Medicine 20(8) 1215-1234
154. 	Lachenbruch, P. A. (2001) "Power and Sample Size Requirements for
Two-part models" Statistics in Medicine 20(8) 1235-1239
158. 	Lachenbruch, P. A. (2002) "Analysis of Data with Excess Zeros"
Statistical Methods in Medical Research 11(4) 297-302

Tony

Peter A. Lachenbruch
Department of Public Health
Oregon State University
Corvallis, OR 97330
Phone: 541-737-3832
FAX: 541-737-4001


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Carlo Lazzaro
Sent: Tuesday, March 17, 2009 10:53 AM
To: statalist@hsphsun2.harvard.edu
Cc: Lachenbruch, Peter
Subject: R: st: Zero-truncated Negative Binomial convergence


Dear Tony,
may I ask you for the reference of the papers in Statistics in Medicine you
mentioned in your reply to the thread Emily started? 

Thanks a lot and Kind Regards,
Carlo
-----Messaggio originale-----
Da: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di Lachenbruch,
Peter
Inviato: martedì 17 marzo 2009 18.16
A: statalist@hsphsun2.harvard.edu
Oggetto: RE: st: Zero-truncated Negative Binomial convergence

If the zeros are identifiable from some other information - e.g.,
hospital costs will be 0 if the patient isn't hospitalized or in this
case we would know the visits to a specialist is 0 if the patient is
only seen for physical exams, etc. - then a two-part model might work.
In this case one uses two models: one for the number of visits if visits
are >0 and one (a logistic) for distinguishing 0 vs. non-zero.  I have a
few papers in Statistics in Medicine in 2001 that may be helpful.  

I would emphasize that in this case, some of the 0 visits to a
specialist are in patients who should have seen a specialist but didn't.

Tony

Peter A. Lachenbruch
Department of Public Health
Oregon State University
Corvallis, OR 97330
Phone: 541-737-3832
FAX: 541-737-4001


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Maarten buis
Sent: Monday, March 16, 2009 2:08 PM
To: stata list
Subject: RE: st: Zero-truncated Negative Binomial convergence


--- Emily Wilson wrote:
> I am having trouble running a zero-truncated negative binomial
> regression. The dependent variable is: # of visits to a
> specialist physician in the past year, and the distribution is 
> something like:
> 0 visits ~= 93,000
> 1 visit ~= 15,000
> 2 visits ~= 1,000
> 3 visits ~= 500

The zero truncated distribution assumes that there are no zeros.
In your case you definately do have zeros. I would start with a 
regular -poisson-, and than I might worry about excess zeros, 
for which you can look at the zero inflated poisson (-zip-), the 
negative binomial (-nbreg-), and zero inflated negative binomial 
(-zinb-). There is a nice discussion of these models and how to
choose between them in this book:
http://www.stata-press.com/books/regmodcdvs.html

Hope this helps,
Maarten

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

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


      

*
*   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/



*
*   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/



*
*   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/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index