Enforcement and illegal migration

Border enforcement of immigration laws raises the costs of illegal immigration, while interior enforcement also lowers its benefits. Used together, border and interior enforcement therefore reduce the net benefits of illegal immigration and should lower the probability that an individual will decide to illegally migrate. While empirical studies find that border and interior enforcement serve as deterrents to illegal immigration, immigration enforcement is costly and carries unintended consequences, such as a decrease in circular migration, an increase in smuggling, and higher prevalence of off-the-books employment and use of fraudulent and falsified documents.