“Both the Census-data driven studies and macro-level studies find that immigrants are less crime-prone than natives with some small potential exceptions. There are numerous reasons why immigrant criminality is lower than native criminality. One explanation is that immigrants who commit crimes can be deported and thus are punished more for criminal behavior, making them less likely to break the law.
Another explanation is that immigrants self-select for those willing to work rather than those willing to commit crimes. According to this ‘healthy immigrant thesis,’ motivated and ambitious foreigners are more likely to immigrate and those folks are less likely to be criminals. This could explain why immigrants are less likely to engage in ‘anti-social’ behaviors than natives despite having lower incomes. It’s also possible that more effective interior immigration enforcement is catching and deporting unlawful immigrants who are more likely to be criminals before they have a chance to be incarcerated.”July 14, 2015