Dr. John Lott has a new op-ed at the Washington Times.
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The claim that illegal aliens commit crimes at lower rates than native-born Americans may look convincing, but it doesn’t hold up under scrutiny. One of the loudest advocates of this narrative has been the libertarian CATO Institute. Its reports, widely covered by the media, continue to help shape public opinion—including its latest release titled “Illegal Immigrant Incarceration Rates, 2010–2023.” They claim that illegal aliens commit crime at half the rate of native-born Americans and that legal immigrants commit crime at just a quarter of the rate.
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But just like their previous similar efforts, this report falls short of credible analysis.
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CATO’s strategy seems to be working. A McLaughlin & Associates survey commissioned by the Crime Prevention Research Center on April 29, 2025—just days after CATO released its latest report—shows that 41.6% of voters now believe illegal immigrants commit fewer crimes than U.S. citizens. Only 33.3% think the opposite.
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To back its claims, CATO once again leans heavily on data from the American Community Survey (ACS). But the institute never adequately explains how flawed this dataset is for measuring crime rates when applied to illegal immigration. The ACS surveys about 3.5 million U.S. addresses each year and asks participants to respond online or by mail. CATO specifically uses ACS data on prison populations to estimate how many inmates are illegal immigrants.
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This method introduces serious bias. The ACS likely undercounts criminal activity among illegal immigrants, leading to skewed results that understate the real scale of the issue.
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For example, immigration authorities often deport undocumented immigrants directly from prison before they finish their sentences. In early 2025, for example, about half of the individuals ICE highlighted in enforcement actions were already incarcerated at the time of their arrest. This practice skews crime data by underrepresenting illegal aliens in prison population statistics.
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ICE’s Enforcement and Removal Operations (ERO) records also show that local jails frequently transfer noncitizens arrested for crimes like DUI, drug possession, or assault to ICE custody—before the offenders serve any time in prison.
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Authorities may also deport illegal aliens after arrest even before conviction or sentencing. These removals typically result from policies that prioritize immigration enforcement over criminal prosecution. Because entering or remaining in the U.S. without authorization already qualifies an individual for deportation, a conviction isn’t required to remove them.
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Meanwhile, the Cato Institute assumes that anyone receiving federal benefits—such as welfare, health care, or Social Security—is in the U.S. legally and that program fraud doesn’t occur. Yet, a 2024 audit by the U.S. Health and Human Services Inspector General under the Biden administration found California improperly claimed $52.7 million in federal Medicaid reimbursements for illegal aliens. Illegal immigrants have fraudulently accessed a wide range of programs, including Social Security and public housing.
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The American Community Survey (ACS) adds another layer of bias. Because the survey is voluntary, undocumented immigrants—whether in prison or not—have a strong incentive to conceal their immigration status. Despite assurances that their answers won’t be shared with law enforcement, inmates know that disclosing their undocumented status could increase their likelihood of deportation. This leads to further underreporting in the ACS data.
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The data offers a clearer link between illegal immigration and crime. In fact, just last year, even the Biden administration admitted that 9% of the so-called “non-detained” illegal immigrants—662,566 out of 7.4 million released into the U.S.—had criminal records. What makes this even more alarming is that these individuals were largely those who voluntarily turned themselves in at the border—the ones supposedly least likely to pose a threat. These numbers don’t even include the 2 million known “gotaways” who crossed the border without being apprehended during the Biden administration, nor the unknown millions who evaded detection entirely. And that 9% figure assumes the administration didn’t undercount criminal records—which is questionable, especially since countries like Venezuela often refuse to share background information on their citizens.
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It is hard to ignore the unprecedented percentage increase in violent crime during the Biden administration as illegal immigrants flooded into the country. And that the U.S. murder rate is on track for the lowest murder rate on record as deportations rise.
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A prior Maricopa County Attorney’s Office study revealed that illegal immigrants committed 21.8% of felonies sentenced in Maricopa County Superior Court, over twice their proportion of Arizona’s population. Mexican nationals alone accounted for 13% of inmates in the state prison system. Other research looking at Arizona state prison data shows Illegal immigrants are at least 142% more likely to be convicted of a crime than other Arizonans.
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CATO has long pushed an open-borders agenda—an approach that even free-market economist Milton Friedman warned would fail in a country with a large welfare system. CATO’s continued selective use of flawed data only reinforces how unreliable its claims are.
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