count.fit

This function compares four models for count responses, namely Poisson regression, negative binomial regression, zero-inflated Poisson regression, and zero-inflated negative binomial regression. To do so, it takes a Poisson regression model object (as specified via glm), and the range on the count outcome. This function mimics the countfit function developed in Long and Freese (2006).

For example:

library(catregs)
data("LF06art")
p1 <- glm(art ~ fem + mar + kid5 + phd + ment , family = "poisson", data = LF06art)
table(LF06art$art)

## 
##   0   1   2   3   4   5   6   7   8   9  10  11  12  16  19 
## 275 246 178  84  67  27  17  12   1   2   1   1   2   1   1

fit<-count.fit(p1,0:19)
names(fit)

## [1] "ic"         "pic"        "models"     "models.pic"

#fit$ic
#fit$pic
#fit$models
#fit$models.pic