R help - May 2005 - Vuong test

Hi,

I have two questions. First, I'd like to compare a ZINB model to a negativ
binomial model with the Vuong test, but I can't find how to performe it from
the zicount package. Does a programm exist to do it ?
Second, I'd like to know in which cases we have to use a double hurdle model
instead of a zero inflated model.

Many thanks,

St??phanie Payet

REES France
R??seau d'Evaluation en Economie de la Sant??
28, rue d'Assas
75006 PARIS
T??l. +33 (0)1 44 39 16 90
Fax +33 (0)1 44 39 16 92
M??l. reesfrance at wanadoo.fr
Site Internet : http://www.rees-france.com

Hi St??phanie,

The Vuong test can be done in Stata
(http://www.stata.com/support/faqs/stat/vuong.html), but I am also
looking for its code in R. In addition to "zicounts", Dr. Simon
Jackman (http://pscl.stanford.edu/) has provided the code for fitting
the zero-inflated (http://pscl.stanford.edu/zeroinfl.r) and hurdle
(http://pscl.stanford.edu/hurdle.r) count models.

Reza



On 5/17/05, St??phanie PAYET <spayet.reesfrance at wanadoo.fr>
wrote:
> Hi,
> 
> I have two questions. First, I'd like to compare a ZINB model to a
negativ
> binomial model with the Vuong test, but I can't find how to performe it
from
> the zicount package. Does a programm exist to do it ?
> Second, I'd like to know in which cases we have to use a double hurdle
model
> instead of a zero inflated model.
> 
> Many thanks,
> 
> St??phanie Payet
> 
> REES France
> R??seau d'Evaluation en Economie de la Sant??
> 28, rue d'Assas
> 75006 PARIS
> T??l. +33 (0)1 44 39 16 90
> Fax +33 (0)1 44 39 16 92
> M??l. reesfrance at wanadoo.fr
> Site Internet : http://www.rees-france.com
> 
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