A group of people held a press conference in Brewster yesterday to call attention to crimes committed by illegal immigrants and to demand that something be done to enforce the immigration laws.
“While crime is crime and the victims suffer equally whether the perpetrator is a citizen or illegal alien, what makes illegal alien crime so different is that the crime would have never happened if our government was doing its constitutionally mandated duty and enforcing immigration laws,” Ed Kowalski said in a press release from 9/11 Families for a Secure America. “This unequal enforcement of the law also makes it much more difficult on the victim’s families.”

Terry Corcoran has a story in today’s Journal News about the event. In essence, the message was that illegal immigrants are an inherent threat because their identities cannot truly be known. And illegal immigrants are by definition contemptuous of the law, the message goes. “Every illegal is a person who has shown contempt for American law, and every employer of illegals is a co-conspirator in any crime perpetrated by an illegal alien,” Kowalski said in his statement.
“Tomorrow’s terrorist is today’s cab driver,” Peter Gadiel said.
Here I’ll look a couple of statistics mentioned at the press conference, suggesting that illegal immigrants commit more crime than other people. The numbers came from Michael Cutler, who said he’d worked in a number of roles at U.S. immigration agencies.
The first claim: “About 30 percent of the inmate population are identified as being illegal aliens.”
Assemblyman Greg Ball has also made this claim in reference to New York state prisons. The actual percentage of inmates who are identified as illegal aliens in New York is 4 percent, according to state corrections officials. According to the Bureau of Justice Statistics, about 6 percent of state and federal inmates are non-U.S. citizens – a group that would include both legal and illegal immigrants. This 2005 report gives further details and percentages. For example, noncitizens accounted for 19 percent of federal inmates. Those federal inmates accounted for just 8 percent of the combined state/federal prison population. Here is the 2007 report, though you have to do the math yourself.
Statistics coming from local jails are not as complete. Eighty-four percent of jails track the numbers of noncitizen inmates, and based on that data, noncitizens accounted for 8 percent of the U.S. jail population in 2007, according to BJS. Again, the 8 percent would include both legal and illegal immigrants.
The “30 percent” figure has been widely circulated, and it comes from a 2005 GAO report that said 27 percent of federal inmates were “criminal aliens.” Again, this is just the federal prison population, and a “criminal alien” can be a legal or illegal immigrant. (In the jargon, a criminal alien is a noncitizen who has been charged with a crime.)
The second claim: “What this really means is that Illegal aliens are about five times as likely to commit a felony as are U.S. citizens and resident aliens.”
Cutler said this calculation is based on the 30 percent figure and the widely accepted estimate that 12 million people in the country are illegal immigrants. Demographer Jeffrey Passel of the Pew Hispanic Center estimates the unauthorized population at 12 million, or 4 percent of the nation’s population.
There have been a number of studies on immigrants and crime. The Public Policy Institute of California examined the incarceration data as a measure of whether immigrants commit more crime than other people. In a 2008 report (click here for the PDF), it found that immigrants are much less likely to be incarcerated than others. It’s difficult to break out the undocumented population, the report said, but it’s possible to compare foreign-born and native-born prisoners with similar education levels and ages.

Because immigrants tend to be young, male and less educated, there would be reason to expect a higher level of criminal activity, not a lower one, the report says. But the foreign-born accounted for 35 percent of California’s adult population and 17 percent of the adult prison population.
The institute looked further: Could the lower incarceration rates be explained by deportation? What about the jail population, which isn’t counted in the prison data? What if you look at only recently-arrived immigrants, or the ones who have accumulated more years here? What if you look at crime rates in individual cities where immigrants are going? What about the children of immigrants? What if you look only at the ones with less than a high school diploma?
The conclusion was that “the foreign-born have low rates of incarceration and institutionalizations, and that these rates hold true across education and region-of-origin subgroups.” The report ends, “In particular, from a public safety standpoint, there would be little reason to further limit immigration, to favor entry by high-skilled immigrants, or to increase penalties against criminal immigrants.”