opsr_2step {OPSR}R Documentation

Heckman Two-Step Estimation

Description

This is a utility function, used in opsr and should not be used directly. Tow-step estimation procedure to generate reasonable starting values.

Usage

opsr_2step(W, Xs, Z, Ys)

Arguments

W

matrix with explanatory variables for selection process.

Xs

list of matrices with expalanatory varialbes for outcome process for each regime.

Z

vector with ordinal outcomes (in integer increasing fashion).

Ys

list of vectors with continuous outcomes for each regime.

Details

These estimates can be retrieved by specifying .get2step = TRUE in opsr.

Value

Named vector with starting values passed to opsr.fit.

Remark

Since the Heckman two-step estimator includes an estimate in the second step regression, the resulting OLS standard errors and heteroskedasticity-robust standard errors are incorrect (Greene 2002).

References

Greene WH (2002). LIMDEP Version 8.0 Econometric Modeling Guide, vol. 2.. Econometric Software, Plainview, New York.

See Also

opsr.fit, opsr_prepare_coefs


[Package OPSR version 0.1.2 Index]