On Mar 4, 2015, at 4:21 AM, "Ben Bolker" <bbolker at gmail.com> wrote:
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?