Authored by: Matt Palumbo

Last week I published a “Debunk This” piece examining whether or not illegal aliens commit crimes at a lower rate than native born Americans, which I was prompted to do after seeing a debate featuring the Cato Institute’s Alex Nowrasteh.

Alex responded and directed me to some criticisms of the studies I cited in making my own case, some of which is necessary to incorporate into my arguments. Dan invited Alex and I to debate the subject on his NRATV show, so ahead of that, I thought I’d address some of the criticisms of my criticism. I’d recommend reading my article “Do Illegal Aliens Really Commit Fewer Crimes” to anyone who hasn’t done so already, before reading this.

Alex linked to some of his writing on John Lott’s immigration study, and the Government Accountability Office’s, both of which I relied on:

Before addressing those criticisms, I think it is worth reiterating my point that any estimates we have of illegal immigrant crime based off of prison statistics are going to be understated for the reasons I mentioned in my initial piece:


  • In America, the average convict released had 3.9 prior convictions (excluding convictions that didn’t result in jail time). Given that many illegal immigrants will simply be deported at the end of their sentence (or be deported in lieu of other punishment), the chance of them re-offending is essentially zero (unless they’re to reenter the U.S.). Thus, we’re working with a biased sample, whereas many of the worst illegal alien offenders are no longer in the U.S. in the first place.
  • Most crime victims in America are victims at the hands of people who look like them. Many of the victims of illegals are likely illegals themselves, or the children of illegals, both of which wouldn’t want to get law enforcement involved.

And since the studies I referenced were based on illegal immigrant prison statistics, there are two other variables that cause illegal alien crime to be understated:

  • Over 60% of illegal aliens live in just 20 sanctuary cities, and some of those cities solve serious crimes at far lower rates than the national average. In 2015, 46% of the violent crimes and 19% of the property crimes reported to police in the U.S. were cleared, according to FBI data. In San Francisco and Los Angeles, only about a third of violent crimes are cleared.
  • There are certain crimes illegals commit that we’re not even considering – such as identity theft/fraud.  The IRS has documented 1.3 million individual cases of employment related identity theft from 2011-2016. While this isn’t the same as aggravated identity theft, the fact that nearly 40 million Social Security numbers have been compromised by illegals isn’t exactly heartwarming.

That aside, let’s dive into the two studies I cited.

John Lott/Arizona Study

Nowrasteh’s main criticism here is that Lott is overstating the number of illegal immigrants by looking at the incarceration rates of “non-citizens,” but that includes people besides illegal aliens (such as someone with a green card, whom Nowrasteh points out account for 10% of those deported).  Fair enough.

To narrow down which “non-citizens” are illegal aliens, Nowrasteh isolates which have ICE detainers outstanding (which require an inmate to be deported at the end of their sentence). About 38% of illegals in his sample had ICE detainers.

There were 1,823 prisoners with ICE detainers in 2017, which out of a prison population of 42,200 amounts to an incarceration rate to be “a maximum of only 4.3% of all prisoners,” compared to the 4.9% of Arizona’s population illegals compose.

Where Nowrasteh and I disagree is in our interpretation of those ICE detainer figures. Nowrasteh sees them as the maximum number of non-citizens that are illegals, which I see that as the absolute minimum. Politics has played a large role in the number of ICE detainers outstanding, with fewer than half being in existence in 2017 than their peak in 2010. Note the figures charted below are overall detainers (not just prisoners), and the same trend holds nationally.

Furthermore, to believe that 62% of the non-citizen prison population in Arizona are non-illegal immigrants would betray everything we know about legal immigrant crime statistics. There are about 13 million legal permanent residents in the U.S., which is similar to the illegal alien population of 10-15 million. Are we to believe that legal immigrants, that have gone through background checks (among all the other hurdles to immigrate), are committing crimes at double the rates of illegal immigrants?

That seems unlikely, and as Lott himself noted, “if we adjust the 2017 rate of detainers during the Trump administration to equal the Fiscal Year 2011 rate, then Nowrasteh’s range of incarceration rates would actually be from 6.79% to 7.89%,” which is greater than their share of Arizona’s population.

GAO Study 

A second study I cited was from the Government Accountability Office, which provided State level illegal immigrant crime statistics based on the State Criminal Alien Assistance Program (SCAAP), which reimburses States for the costs of illegal immigrant prisoners. That report found that in 2009 there were 295,959 criminal aliens in state, local, and federal prisons, which Nowrasteh says suffers from double-counting, because the 295k figure is based on total incarcerations, not incarcerated individuals.

As an alternative figure, Nowrasteh uses the American Community Survey (ACS), a Census-like survey that (among many other things) garners data on prisoners, including whether or not they’re American citizens, and their country of birth. Nowrasteh cites 156,329 non-citizens incarcerated at the federal, state, and local level in 2008, about half the SCAAP figure. Of course, this is self-reported data, and some non-citizens could slip through the cracks when it comes to reporting their citizenship status.

Again, the disagreement between Nowrasteh and I appears to be in how to interpret both studies. In my view the SCAAP survey is an absolute maximum figure for illegals incarceration. While it does suffer from double counting, it’s hard to imagine it’s by a large extent, unless we’re to believe that the illegals are only being incarcerated for months at a time, then immediately re-offending, and all without risking deportation. Meanwhile, I’d view the ACS figure as a minimum.

Since the truth is likely somewhere in the middle, and it’s not possible to know, I’ll be retiring this study in the future (which unfortunately means I’ll have to retract the snarky comment at the end of my prior essay). I will note however that there is another way to look at the data, based on the percentage of overall prison time illegals serve, rather than the percentage of prisoners they compose.  According to the 2009 SCAAP data, illegal aliens accounted for 5 and 6 percent of the total days of prison time served in state and local jails, respectively. If we’re to assume 12.5 million illegal aliens in America and an overall population of 325 million, illegals account for 3.8% of the population.


And Let’s Suppose I’m Wrong

Hypothetically speaking, let’s say I’m wrong that illegal aliens commit crimes at rates higher than native born Americans. That still doesn’t change the fact that there are crimes being committed that otherwise wouldn’t have happened. Suppose for the sake of a thought experiment that there was a city of 1 million people, and an additional 1 million illegals began living in the city. In the sake of this thought experiment, natives are victimized at a rate 85% higher than they were before the influx of illegals, due to increased crime from the illegal share of the population.

But at the same time, the population of the city doubled, meaning there would be simultaneously more native victims of crime, and yet the crime statistics would actually appear to decrease. Would any of those victimized notice (or find comfort in knowing) that they were technically being victimized at a lower statistical rate?