Four Parameters of Interest in the Evaluation of Social Programs

This paper reviews four treatment parameters which have become commonly used in the program evaluation literature: the Average Treatment Effect (ATE), the effect of Treatment on the Treated (TT), the Local Average Treatment Effect (LATE) and the Marginal Treatment Effect (MTE). We derive simply computed closed-form expressions for these treatment parameters in a latent variable framework with Gaussian error terms. We also briefly describe recent work which seeks to go beyond mean effects and estimate the distributions associated with various outcome gains.