The alleged murder of Kate Steinle in San Francisco by illegal immigrant Juan Francisco Lopez-Sanchez has reignited the debate over the link between immigration and crime. Such debates often call for change in policy regarding the deportation or apprehension of illegal immigrants. However, if policies should change, it should not be in reaction to a single tragic murder. It should be in response to careful research on whether immigrants actually boost the U.S. crime rates.
With few exceptions, immigrants are less crime prone than natives or have no effect on crime rates. As described below, the research is fairly one-sided.
There are two broad types of studies that investigate immigrant criminality. The first type uses Census and American Community Survey (ACS) data from the institutionalized population and broadly concludes that immigrants are less crime prone than the native-born population. It is important to note that immigrants convicted of crimes serve their sentences before being deported with few exceptions. However, there are some potential problems with Census-based studies that could lead to inaccurate results. That’s where the second type of study comes in. The second type is a macro level analysis to judge the impact of immigration on crime rates, generally finding that increased immigration does not increase crime and sometimes even causes crime rates to fall.