[R-sig-ME] Zero-inflated mixed models

[Ben Bolker]

Zahwa Al Ayyash (Student <zsa11 at ...> writes:

> 
> Dear all,
> 
> Zero-inflated models have a count component 
> (Poisson/Neg. Binomial) and a zero component (logistic
> regression part).
 
> glmmADMB supports the zero-inflation feature but only through
> estimating a zero-inflation parameter that is assumed constant
> across the whole data set?.
 
>   1.  ?Why doesn't the glmmadmb support the two-stage fitting of
> zero-inflated models like it does with hurdle models? I once read
> that its estimation might be more complex than that of hurdle
> models. Is that true? If yes, why?

  It doesn't support it because we never got around to implementing
it -- i.e. making sure the interface was well designed, implementing,
and testing.

>   2.  Is there an R package that allows for the two-model fitting
> (i.e., each model with its own covariates) of ZIP or ZINB (not
> hurdle) and allowing for a random effect?

  You can take a look the stuff here:

https://groups.nceas.ucsb.edu/non-linear-modeling/projects/owls/WRITEUP/owls.pdf
https://groups.nceas.ucsb.edu/non-linear-modeling/projects/owls
https://groups.nceas.ucsb.edu/non-linear-modeling/projects/owls/R/owls_R_funs.R

search for 'zipme.f' in the source code.

  Ben Bolker