Rise in immigration may help explain drop in violent crimes

Published 14 May 2010

Contrary to public perception, increased immigration into the United States contributes to a decline in violent crime; new study of crimes rates in 459 American cities with populations of at least 50,000 shows that cities that experienced greater growth in immigrant or new-immigrant populations between 1990 and 2000 also demonstrate sharper decreases in homicide and robbery; the research finds that, controlling for a variety of other factors, growth in the new immigrant population was responsible, on average, for 9.3 percent of the decline in homicide rates, and that growth in total immigration was, on average, responsible for 22.2 percent of the decrease in robbery rates

Immigrants in the early 20th century // Source: samlaget.no

During the 1990s, immigration into the United States reached record highs and crime rates fell more precipitously than at any time in U.S. history. Moreover, cities with the largest increases in immigration between 1990 and 2000 experienced the largest decreases in rates of homicide and robbery, a University of Colorado at Boulder researcher has found.

Tim Wadsworth, an assistant professor of sociology, has tested the hypothesis, famously advanced by Harvard sociologist Robert J. Sampson, that the rise in immigration could be related to the drop in crime rates.

Wadsworth noticed Sampson’s argument in a 2006 New York Times op-ed piece (“Open Doors Don’t Invite Criminals,” 11 May 2006 New York Times). As Wadsworth recalled, “My reaction was that this is really interesting, and it’s a very testable question.” New research supports Sampson’s hypothesis, Wadsworth reports in the June edition of Social Science Quarterly.

Cities that experienced greater growth in immigrant or new-immigrant populations between 1990 and 2000 tended to demonstrate sharper decreases in homicide and robbery,” Wadsworth writes. “The suggestion that high levels of immigration may have been partially responsible for the drop in crime during the 1990s seems plausible.”

Drawing from the FBI’s Uniform Crime Reports and U.S. Census data, Wadsworth analyzed 459 cities with populations of at least 50,000. Wadsworth measured immigrant populations in two ways: those who are foreign-born and those who immigrated within the previous five years.

Wadsworth focused on medium and large cities because about 80 percent of violent crime takes place there. Wadsworth said distinguishing legal and illegal immigration is difficult, as the U.S. Census does not track those numbers, but he notes that immigrant citizens and non-citizens often live together in the same communities.

He tracked crime statistics for homicide and robbery because they tend to be reported more consistently than other crimes. Robberies are usually committed by strangers — which increases the reporting rate — and “homicides are difficult to hide,” he said.

Wadsworth’s findings contradict much of the public rhetoric about the relationship between immigration and crime. As the Arizona Republic reported this month, violent crime in that state’s border towns has remained essentially flat during the past decade even as drug-trade violence on the other side of the border has burgeoned.

The presumed link between immigration and crime has a long history in the United States and overseas. Wadsworth said such sentiments are often expressed on Internet blogs and elsewhere.

Wadsworth contends that looking at crime statistics