unauthorized for US employment (Carroll et al. 2005). Farm employers are justifiably
concerned since these statistics clearly highlight their vulnerability to changes in immigration
policy that may curtail their access to foreign labor.
Given this context, the purpose of this paper is to evaluate the implications of U.S.
immigration policy reform for U.S. farm labor market outcomes, focusing specifically on
proposed legalization for unauthorized immigrant workers. The study uses a treatment effects
(TE) framework in which legalization is modeled as a treatment or (policy) intervention. The TE
framework is a novel approach to immigration policy evaluation that has not been used in
previous studies that have evaluated the potential impact of legalization for farm outcomes. The
paper is organized as follows. Following this introduction, the second section comprises the
analytical framework employed in the study, and the third section presents the study findings.
Policy implications and concluding remarks are given in the final sections of the paper.
Treatment Effects Approach
The treatment effects approach measures the impact of “treatment” on outcomes of
interest. In this context, treatment may refer to medical treatments, public programs or social
interventions (Basu et al. 2007), and the causal effect of the treatment on the outcome is defined
as the treatment effect. The standard problem involves the inference of a causal connection
between participation (treatment) (D) and the potential outcome (Y), where the potential
outcomes for the participant (treated) (Y1 ) and non-participant (non-treated) (Y0 ) states are
compared for the ith individual to evaluate how his average economic outcome would change if
he were to participate in a program or not. Following the latent variable framework of Heckman,
Tobias and Vytlacil (2001; 2003) and Blundell and Costa Dias (2002), the potential outcomes