logLik-methods {twopartm}

Method for Function logLik for Two-part Model Objects in Package twopartm

Description

The logLik method for twopartm-class that extracts log-likelihood from a fitted two-part regression model object of class twopartm.

Usage

## S4 method for signature 'twopartm'
logLik(object,...)

Arguments

object

a fitted two-part model object of class twopartm as returned by tpm.

...

arguments passed to logLik in the default setup.

Details

The logLik method for twopartm-class returns an object of class logLik, including the log likelihood value with degree of freedom of a fitted two-part regression model object of class twopartm.

Value

Returns an object of class logLik for model object twopartm.This is a number with at least one attribute, "df" (degrees of freedom), giving the number of (estimated) parameters in the two-part model.

Author(s)

Yajie Duan, Birol Emir, Griffith Bell and Javier Cabrera

References

Belotti, F., Deb, P., Manning, W.G. and Norton, E.C. (2015). twopm: Two-part models. The Stata Journal, 15(1), pp.3-20.

Harville, D.A. (1974). Bayesian inference for variance components using only error contrasts. Biometrika, 61, 383–385. doi: 10.2307/2334370.

See Also

twopartm-class, glm,logLik.lm, tpm

Examples

##data about health expenditures, i.e., non-negative continuous response
data(meps,package = "twopartm")


##fit two-part model with the same regressors in both parts, with logistic
##regression model for the first part, and glm with Gamma family with log
##link for the second-part model
tpmodel = tpm(exp_tot~female+age, data = meps,link_part1 = "logit",
family_part2 = Gamma(link = "log"))

tpmodel

##summary information
summary(tpmodel)

##log-likehood
logLik(tpmodel)