Sample selection bias as a speciation error
Publication Source
Heckman, J.J.
1978
Publication Title
Econometrica
Publication Type
Journal article
Abstract
This paper discusses the bias that results from using nonrandomly selected samples to estimate behavioral relationships as an ordinary specification error or "omitted variables" bias. A simple consistent two stage estimator is considered that enables analysts to utilize simple regression methods to estimate behavioral functions by least squares methods. The asymptotic distribution of the estimator is derived.