IMR: Inverse Mills Ratio (IMR) Calculation

View source: R/IMR.R

IMRR Documentation

Inverse Mills Ratio (IMR) Calculation

Description

Computes the column vector of the Inverse Mills Ratio (IMR) from a Probit selection equation.

Usage

IMR(selection, data = sys.frame(sys.parent()))

Arguments

selection

A formula specifying the selection equation.

data

A data frame containing the variables in the model.

Details

This function fits a Probit model to the provided selection equation and returns the Inverse Mills Ratio (IMR) for each observation. The IMR is useful for correcting sample selection bias in regression models, following the classical Heckman approach.

Value

A numeric matrix with one column containing the IMR values for each observation.

Examples

data(MEPS2001)
attach(MEPS2001)
selectEq <- dambexp ~ age + female + educ + blhisp + totchr + ins + income
IMR(selectEq, data = MEPS2001)


ssmodels documentation built on June 8, 2025, 10:49 a.m.