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hurdle negative binomial models with MCMCglmm

6 messages · Zelda Van der Waal, David Atkins, Ben Bolker

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Dear all,

I am very new at using MCMCglmm, and would like to fit a hurdle negative binomial distribution model with this package. Does anyone know whether this is possible? as this family is not amongst the distribution families described in the package vignette. 

thanks a lot

.zelda.
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Zelda--

You might take a look at a tutorial paper we have written on mixed model 
count regression; it also includes R code and two datasets:

http://depts.washington.edu/cshrb/newweb/statstutorials.html

[last ms on the page]

The R code provides some details on using MCMCglmm for zero-altered 
models (including zero-inflated and hurdle mixed models).

Hope it helps.

cheers, Dave


Dear all,

I am very new at using MCMCglmm, and would like to fit a hurdle negative 
binomial distribution model with this package. Does anyone know whether 
this is possible? as this family is not amongst the distribution 
families described in the package vignette.

thanks a lot

.zelda.
1 day later
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Many thanks Dave for this link, this is very useful!

However I can only see zero-altered models using Poisson distribution.
Is there a way to use negative binomial distribution in zero-altered models (zero-inflated and hurdle) with mixed effects in MCMCglmm?

thanks again to everyone

.zelda.
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On 12/11/11 1:25 AM, Zelda Van der Waal wrote:
No, MCMCglmm does not fit a negative binomial model (with or without 
zero component).

However, it does fit an "over-dispersed" Poisson, which includes an 
additional, per-observation random-effect.  Although this is not 
identical to a negative binomial, they are often functionally quite 
similar, and the OD Poisson model is almost always a far superior fit a 
straight Poisson.  In fact, MCMCglmm automatically fits this model (the 
"units" term in the output is the over-dispersion random-effect).

If you are truly committed to a zero-inflated negative binomial, the 
glmmADMB package has some facility for fitting these models; however, I 
believe their are some restrictions on how covariates enter the logit 
vs. count portions of the model.  At least, it seemed that way when I 
perused them a while back.  Ben Bolker could speak more to what is (or 
is not) possible via glmmADMB.

Hope that helps.

cheers, Dave

Dave Atkins, PhD
Research Associate Professor
Department of Psychiatry and Behavioral Science
University of Washington
datkins at u.washington.edu

Center for the Study of Health and Risk Behaviors (CSHRB)		
1100 NE 45th Street, Suite 300 	
Seattle, WA  98105 	
206-616-3879 	
http://depts.washington.edu/cshrb/
(Mon-Wed)	

Center for Healthcare Improvement, for Addictions, Mental Illness,
   Medically Vulnerable Populations (CHAMMP)
325 9th Avenue, 2HH-15
Box 359911
Seattle, WA 98104
http://www.chammp.org
(Thurs)
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thanks again Dave, i will give a go to the glmmADMB package as it seems to fit the distributions i am after i.e. both Poisson and negative binomial.

.zelda.
1 day later
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Zelda Van der Waal <z.van-der-waal at ...> writes:
the distributions i am after i.e.
If you need hurdle (rather than zero-inflated) models in glmmADMB, 
please contact me off-list.

  Ben Bolker