The U.S. 1986 Immigration Reform and Control Act and undocumented migration to the United States

One of the major goals of the 1986 Immigration Reform and Control Act (IRCA) is to reduce the number of undocumented immigrants coming to and residing in the United States. This goal is pursued by allocating increased resources to Border Patrol enforcement, imposing penalties on employers for hiring undocumented workers, and offering to legalize the undocumented population that has resided in the country for a substantial period of time. This paper evaluates the impact of IRCA on the flow of undocumented migrants across the U.S.-Mexican border by analyzing a monthly time series of Border Patrol apprehensions from January 1977 to September 1988 within the context of a multivariate statistical model. The model provides a good fit to the data (R² = 0.94), and our results indicate that INS resources, Mexican population growth, comparative economic conditions on both sides of the border, and seasonal factors related to the agricultural planting and harvesting cycle are all determinants of border apprehensions and, by implication, of the flow of undocumented migrants to the United States. IRCA's impacts on the number of ‘apprehensions averted’ operate mainly through changes in INS effort, the SAWs agricultural legalization program, and other IRCA-related factors. Our analysis concludes that the effects of IRCA, though perhaps smaller than sometimes alleged, were associated with a cumulative net reduction in linewatch apprehensions of nearly 700,000 in the 23-month period following enactment of the law. The associated reduction over the same period in the number of illegal border crossings may be as high as 2 million.