Count Data Models
Count data models have a dependent variable that is counts (0, 1, 2, 3, and so on). Most of the data are concentrated on a few small discrete values. Examples include: the number of children a couple has, the number of doctors visits per year a person makes, and the number of trips per month that a person takes.
Handouts, Programs, and Data
Count Data Models Stata Program and Output
Count Data Models R Program and Output
Count Data Models SAS Program and Output
Count data models: topics covered
Poisson model (properties of the distribution, coefficients, and marginal effects)
Negative binomial model (test for overdispersion and incidence rate ratios)
Hurdle or two-part models
Zero-inflated models