This paper compares the structural approach to economic policy analysis with the program evaluation approach. It offers a third way to do policy analysis that combines the best features of both approaches. We illustrate the value of this alternative approach by making the implicit economics of LATE explicit, thereby extending the interpretability and range of policy questions that LATE can answer.

Sample selection bias as a specification error This paper discusses the bias that results from using non-randomly 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.

This paper examines the argument presented in The Bell Curve. A central argument is that one factor--g--accounts for correlation across test scores and performance in society. Another central argument is that g cannot be manipulated. These arguments are combined to claim that social policies designed to improve social performance cannot be effective. A reanalysis of the evidence contradicts this story. The factors that explain wages receive different weights than the factors that explain test scores. More than g is required to explain either. Other factors besides g contribute to social performance, and they can be manipulated.