neg_binomial_2 {rstanarm}

Family function for negative binomial GLMs

Description

Specifies the information required to fit a Negative Binomial GLM in a similar way to negative.binomial. However, here the overdispersion parameter theta is not specified by the user and always estimated (really the reciprocal of the dispersion parameter is estimated). A call to this function can be passed to the family argument of stan_glm or stan_glmer to estimate a Negative Binomial model. Alternatively, the stan_glm.nb and stan_glmer.nb wrapper functions may be used, which call neg_binomial_2 internally.

Usage

neg_binomial_2(link = "log")

Arguments

link

The same as for poisson, typically a character vector of length one among "log", "identity", and "sqrt".

Value

An object of class family very similar to that of poisson but with a different family name.

Examples

if (.Platform$OS.type != "windows" || .Platform$r_arch != "i386")
stan_glm(Days ~ Sex/(Age + Eth*Lrn), data = MASS::quine, seed = 123,
         family = neg_binomial_2, QR = TRUE, algorithm = "optimizing") 
                
# or, equivalently, call stan_glm.nb() without specifying the family