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A new study examined how increasing the number of visas available to potential migrants would affect unauthorized immigration from Mexico to the United States. Current U.S. policy bans people who are deported from receiving legal status for a period of time; this policy, called a legal entry ban, is designed to deter unauthorized immigration, but may not work for many Mexican immigrants. The study found that legal entry bans for deported individuals are ineffective at encouraging legal immigration, but increased legalization rates could reduce illegal immigration. The study also found that a temporary work visa program could deter illegal immigration without resulting in large increases in the number of migrants living in the United States.

The study, by researchers at Carnegie Mellon University (CMU), is a working paper of the National Bureau of Economic Research.

"Understanding the interactions between immigration enforcement and legal immigration policies is important for contemporary immigration policy debates," says Brian K. Kovak, assistant professor of economics and public policy at CMU's Heinz College, who led the study. "In certain contexts, temporary work visa programs may provide more feasible means of providing legal access to the U.S. labor market while still amplifying the deterrent effects of immigration enforcement policies."

Since 2005, the U.S. workforce has included nearly 8 million unauthorized immigrants. U.S. employers demand these workers' services despite potential sanctions and significant barriers to employment facing unauthorized workers. Because U.S. immigration policy is restrictive, most potential immigrants can live and work legally in the United States only if they have a close family member who is a U.S. citizen or permanent resident.

In this study, researchers looked at how increasing the number of visas available to potential migrants would affect the flow of unauthorized immigrants from Mexico to the United States. They used data from the Mexican Migration Project, a joint program of Princeton University and the University of Guadalajara, that surveys Mexican households. In all, they analyzed the international migration circumstances, decisions, and outcomes of 17,538 migrants (primarily male) ages 18 to 65 from 1997 to 2018.

The researchers developed a model that considered the effects of changing enforcement policies and opportunities to obtain legal status using various counterfactual immigration policies and three different outcomes. Because many migrants move temporarily and repeatedly, the dynamic nature of the study's model helped the researchers understand the implications of migration policy for decisions about migration.

The study found that deporting more migrants reduced the number of unauthorized migration to the United States and reduced the cumulative number of years a potential spends living in the United States as an unauthorized immigrant. But even when increasing deportation rates, the policy of excluding those with prior deportations had little effect on rates of unauthorized migration because the likelihood of an unauthorized immigrant obtaining legal status is low. Only in instances where unauthorized immigrants were already likely to gain legal status did the legal entry ban policy reduce unauthorized migration. These findings confirm the value migrants place on having the opportunity to move to the United States legally.

Although more chances to achieve legal status deter unauthorized immigration, they also increase the number of authorized living permanently in the United States. The study considered the effects of expanding access to temporary work visas, which allow migrants to work in the United States for a fixed period of time, after which they must return home. The study found that permanent and temporary visas reduce unauthorized immigration—with temporary visas having less of an impact. This suggests that expanding the number of temporary work visas would help deter unauthorized migration without resulting in significant increases in the overall number of migrants living in the United States.

The relationship between enforcement and legal immigration informs whether to enact different policies simultaneously or sequentially. Many of the comprehensive immigration reforms that have been proposed in the last 25 years include simultaneously increasing enforcement and expanding temporary worker programs. This study suggests that these policies would reinforce one another in reducing unauthorized immigration to the United States.

However, another approach requires reductions in unauthorized migration prior to increasing the options for legal migration. This sequential approach is implemented either through the use of trigger clauses within a single piece of legislation or by legislation focused exclusively on enforcement. While there may be justifications for the sequential approach, they suggest that achieving a reduction in unauthorized migration will be more costly without increased legal access to the United States than when implementing both sets of policies simultaneously.

"Our findings have important implications for structuring future immigration reforms," says Rebecca Lessem, assistant professor of economics in the Tepper School of Business at CMU, the study's coauthor.

More information: Brian Kovak et al, How do U.S. Visa Policies Affect Unauthorized Immigration?, (2020). DOI: 10.3386/w26790