Zero inflation parameter in glmmadmb

Dear list,

The glmmadmb package uses zero-inflated (ZI) models to account for the excess of zero observations in the data. In the package manual, it has been mentioned that ZI models capture that aspect through the estimation of "pz" (zero inflation parameter) which is assumed constant as it is not modeled as a function as covariates like it is the case with hurdle models.


The package outputs its value along with the standard deviation. What does the estimated parameter indicate?


I would like to know more about how this parameters gets estimated for every individual. Are there available references that I can refer to?

Thank you a lot for any help in this!
Zahwa

Graduate Student, American University of Beirut