The debate on immigration is an angry one, filled with anxiety, prejudice and extreme positions. Immigration is said to lead to an increase in crime rates, because the immigrants are often poor, undereducated and not well adjusted to their host community. Illegal immigrants, especially, are believed to be overrepresented in crime statistics because they are hard to track down, have no official residence, and can easily escape across the border.
However, none of this stands the test of critical examination of facts, at least when we limit ourselves to the situation in the US.
A study by Kristin F. Butcher and Anne Morrison Piehl – Crime, Corrections and California: What Does Immigration Have to Do With It? – concludes that immigrants in California, including “undocumented” persons, are far less likely than their native-born counterparts to commit crime. Additionally, to test for the possibility that immigrants might be simply avoiding incarceration by leaving the country, the study looked at crime rates in California cities with the largest influx of immigrants, including Los Angeles, San Francisco and Sacramento. The study found that on average, the crime rates in those cities dropped between 2000 and 2005. (source)
These numbers are very convincing, even if we accept some dubious caveats (illegal immigrants, when committing a crime, are perhaps more likely to flee abroad and hence not end up in incarceration statistics, and immigrant communities perhaps underreport crime). Politicians should therefore stop exploiting irrational fears about immigrant crime.