Negative-binomial family for glmm()

NB2 family (variance mu + mu^2/theta, log link). With theta = NULL (the default) the size parameter is estimated alongside the model, matching lme4::glmer.nb(). Supplying a positive theta fits conditional on that value, matching glmer(family = MASS::negative.binomial(theta)) — which glmm() also accepts directly.

Usage

mm_negative_binomial(theta = NULL)

Arguments

theta

Optional positive NB2 size (dispersion) parameter. NULL estimates theta from the data.

Value

A family object accepted by glmm().

Examples

fam <- mm_negative_binomial()      # glmer.nb-style: theta estimated
fam_fixed <- mm_negative_binomial(theta = 2.5)