Although research has consistently shown that immigrants have lower crime rates than the native-born population, testing for possible "indirect" effects on crime rates, e.g. by leading native-born Americans affected by hypothetical job displacement to turn to lives of crime, has been minimal. This study attempts to remedy this gap in research. The authors investigate the immigration-crime relationship within 200 metropolitan statistical areas (MSAs) over a 40-year time period from 1970 to 2010.  By pushing the time frame back to 1970 (the horizon for most recent studies is much shorter), this research has the advantage of including periods of both economic stress and expansion. The study examines rates (per 100,000 people) of murder, non-negligent manslaughter, aggravated assault, robbery, burglary, and larceny at five points in time (1970, 1980, 1990, 2000, and 2010).  The results show that "the presence of immigrants consistently helped to decrease violent and property crime in U.S. metropolitan areas" and thus suggestions that immigrants contribute to crime through "structural" or "macro-level" mechanisms are unfounded.  The paper also contains a useful summary of research to date on the question of immigration and crime.

Review of recent research casts doubt on President Trump's claims that immigrants are prone to crime

According to the authors of this report, the impact of immigration on crime rates in the United States is a "well-examined field of study" which has produced "a rigorous body of research."  After summarizing this research, the authors conclude that President Donald Trump "has made demonstrably false claims associating immigrants with criminality." The report covers research in three areas:  immigrant crime rates compared to native-born individuals, the relationship between rising immigration and falling crime rates in local communities, and incarceration rates in federal and state prisons. In the first area, the authors focus on adolescent and undocumented criminality, citing studies showing that "foreign-born youth...had among the lowest delinquency rates when compared to their peers" and that "immigrants - regardless of legal status - do not have higher crime rates than native-born citizens."  In the second area, the authors reference several studies that find a connection between increases in immigration and decreases in crime rates in cities and metropolitan areas, including one study that found a similar inverse relationship at the neighborhood level in Chicago. Finally, the authors disaggregate the U.S. prison population to explain the over-representation of non-citizens in the federal system, and their underrepresentation in the state. Although non-citizens are slightly underrepresented in U.S. prisons as a whole, they are greatly underrepresented in state prisons, where non-citizens make up only four percent of the population (of the 1.5 million people imprisoned in state and federal prisons, 87 percent are held in state institutions).  Within federal prisons, however, 22 percent are non-citizens, largely resulting from the criminalization of immigration violations since 2000 (66 percent of all federal sentences imposed in 2015 were for immigration violations).  The authors conclude that "false statements about immigrant criminality contribute to unfounded public fears that threaten the safety of immigrants and U.S. citizens."