[R-sig-eco] hurdle model

[Gavin Simpson]

On Thu, 2010-08-19 at 09:52 +0200, Yingjie Zhang wrote:
> Hello everyone,
> 
> Does anyone of you using hurdle model? I am reading a paper which said
> " Hurdle model removes effect of zero-inflation and over-dispersion in
> the non-zero observations using a quasi-likelihood", I've checked the
> help file from hurdle in R, which said differently that"for non-zero
> obs normally a truncated poisson/NB is used" ... just want to make
> sure, does it really estimated the parameter by "quasi-likelihood"
> 
> Thanks,
> Yingjie Zhang
> Biostatistician

The authors of that paper might have fitted their hurdle model using a
quasi likelihood but that is not, AFAICT, what is used in the hurdle()
function in package 'pscl', which maximises a proper log likelihood.

But hard to say from what you have provided.

G
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