John R. Lott, Crime Prevention Research Center, February 18, 2018
Using newly released detailed data on all prisoners who entered the Arizona state prison from January 1985 through June 2017, we are able to separate non-U.S. citizens by whether they are illegal or legal residents. Unlike other studies, these data do not rely on self-reporting of criminal backgrounds. Undocumented immigrants are at least 142% more likely to be convicted of a crime than other Arizonans. They also tend to commit more serious crimes and serve 10.5% longer sentences, more likely to be classified as dangerous, and 45% more likely to be gang members than U.S. citizens. Yet, there are several reasons that these numbers are likely to underestimate the share of crime committed by undocumented immigrants. There are dramatic differences between in the criminal histories of convicts who are U.S. citizens and undocumented immigrants.
Young convicts are especially likely to be undocumented immigrants. While undocumented immigrants from 15 to 35 years of age make up slightly over two percent of the Arizona population, they make up about eight percent of the prison population. Even after adjusting for the fact that young people commit crime at higher rates, young undocumented immigrants commit crime at twice the rate of young U.S. citizens. These undocumented immigrants also tend to commit more serious crimes.
If undocumented immigrants committed crime nationally as they do in Arizona, in 2016 they would have been responsible for over 1,000 more murders, 5,200 rapes, 8,900 robberies, 25,300 aggravated assaults, and 26,900 burglaries.
[Editor’s Note: The entire report may be downloaded as a PDF document at no charge here.]