Estimates the parameters of the classic Heckman model via the two-step method.
HCinitial(selection, outcome, data = sys.frame(sys.parent()))Selection equation.
Primary Regression Equation.
Database.
Returns a numerical vector with estimates of the parameters of the classical Heckman model using the two-step method
Generally, the two-step method is very useful for finding initial values for the Likelihood Estimation method. In first step performs a probit analysis on a selection equation. The second step analyzes an outcome equation based on the first-step binary probit model.
data(MEPS2001)
attach(MEPS2001)
selectEq <- dambexp ~ age + female + educ + blhisp + totchr + ins + income
outcomeEq <- lnambx ~ age + female + educ + blhisp + totchr + ins
HCinitial(selectEq,outcomeEq, data = MEPS2001)
#> xs(Intercept) xsage xsfemale xseduc xsblhisp
#> -0.668643899 0.086814848 0.663505390 0.061883892 -0.365784312
#> xstotchr xsins xsincome xo(Intercept) xoage
#> 0.795747277 0.169106526 0.002677301 5.288927373 0.202466773
#> xofemale xoeduc xoblhisp xototchr xoins
#> 0.292133967 0.012388871 -0.182865733 0.500633176 -0.046509658
#> sigma rho
#> 1.290541875 -0.359316986