The belief that immigrants bring violent crime with them when they cross into the U.S. is a pernicious myth that nearly half of Americans cling to, despite the fact there are no credible data to support the belief.
President Donald Trump has pointed to the idea of the 'criminal illegal immigrant' repeatedly since he first announced his bid for the presidency, most recently in a series of tweets between Friday and Monday.
In those tweets, Trump calls for stronger immigration laws to keep dangerous "caravans" of immigrants from crossing the southern border.
Fox News personalities have also worked to keep the notion of rampant immigrant crime at the front of Americans' minds:
But while America's immigration policy should be open to debate and improvements applied where necessary, it should not include the trope that immigrants bring violent crime into our communities.
The Washington Post has broken down one of the most comprehensive studies investigating the potential relationship between immigration and violent crime, and the results are in line with the vast majority of similar research: either increased immigration brings average crime rates down, or there is no relationship between the two at all.
In a large-scale collaboration by four universities, led by Robert Adelman, a sociologist at the State University of New York at Buffalo, researchers compared immigration rates with crime rates for 200 metropolitan areas over the last several decades. The selected areas included huge urban hubs like New York and smaller manufacturing centers less than a hundredth that size, like Muncie, Ind., and were dispersed geographically across the country.
In a majority of areas, the number of immigrants increased at least 57 percent and as much as 183 percent, with the greatest increases occurring in the 1990s and early 2000s. Violent crime rates in most areas ranged between a 43 percent decline and a 6 percent rise, often trending downward by the 2000s. Places with a sharp rise in the immigrant population experienced increases in crime rates no more frequently than those with modest or no growth in immigration. On average, the immigrant population grew by 137 percent between 1980 and 2016, with average crime falling 12 percent over the same period.
In general, the study’s data suggests either that immigration has the effect of reducing average crime, or that there is simply no relationship between the two, and that the 54 areas in the study where both grew were instances of coincidence, not cause and effect. This was a consistent pattern in each decade from 1980 to 2016, with immigrant populations and crime failing to grow together.
And as for undocumented immigrants?
The foreign-born data, which is collected through the census, most likely undercounts the numbers of undocumented immigrants, many of whom might wish to avoid the risk of identifying themselves. They are, however, at least partly represented in the overall foreign-born population counts.