Last year we published a blog summarizing the research on how immigrants affect the crime rate in the United States. There are two major types of studies that examine this question.
The first uses Census data of the institutionalized population to investigate immigrant versus native incarceration rates. Although the Census evidence isn’t perfect because of potential issues with reporting immigration status and different types of incarceration, these studies show that immigrants are less likely to be incarcerated than similarly-aged natives. The second type is a macro-level or area study that looks at the crime rates in places that have experienced large waves of immigration. These generally find that immigration either lowers or has little effect on crime rates. The research on unauthorized immigrant crime rates is poor.
A few recent papers recently extended these findings. The first by David Green seeks to determine whether immigrants affect violent and drug-related crime in the United States on the state-level. It looks at state-level rates of violent crime and drug arrests pooled for the 2012-2014 years against pooled statistics on foreign-born and Mexican nationals by immigration status, specifically legal versus unauthorized immigrants. Green finds no association between immigrant population size and increased violent crime. However, he does find a small but statistically significant association between unauthorized immigrant population size and arrests for drug offenses.