LL_poisson {gspcr}

Poisson regression log-likelihood

Description

Computes the Poisson regression log-likelihood of a vector of observed values given the GLM systematic component.

Usage

LL_poisson(y, x, mod)

Arguments

y

numeric vector recording a count dependent variable.

x

data.frame (or matrix) containing predictor values.

mod

glm object containing the estimated poisson regression model.

Details

If x and y are equal to the data on which mod has been trained, this function returns the same result as the default logLink function. If x and y are new, the function returns the log-likelihood of the new data under the trained model.

Value

A list containing:

• ll an atomic vector of length 1 containing the log-likelihood value.

• sc an atomic vector containing the systematic component for the input x and mod.

Author(s)

Edoardo Costantini, 2023

References

Agresti, A. (2012). Categorical data analysis (Vol. 792). John Wiley & Sons.