Crime Rates, Not the Number of Crimes, Are a Better Way to Judge Immigrant Criminality

By Alex Nowrasteh of Cato.

"Yesterday, the House Committee on Oversight and Accountability, Subcommittee on National Security, the Border, and Foreign Affairs held a hearing titled “How the Border Crisis Impacts Public Safety.” My colleague David Bier testified. One of the other witnesses was Ken Cuccinelli, former attorney general of Virginia, who also served in various capacities at the Department of Homeland Security. Cuccinelli submitted written testimony about the impact of illegal immigration on crime, stating, “Crime rates do not matter, only the raw number of crimes and the harm caused by those crimes.”

Cuccinelli was trying to refute Cato Institute research that finds illegal immigrants and legal immigrants have a consistently lower criminal conviction rate and incarceration rate than native‐​born Americans by channeling a common refrain I hear on Twitter and from immigration restrictionists: ‘Some immigrants commit crimes, and those crimes would not have occurred in the United States if the immigrants weren’t here.’ In an obtuse way, they have a point. But it’s a trivial point because some individuals in any large population will always commit some crimes. Even small populations of people disinclined to commit crimes contain a few individuals who occasionally do, such as female biology professors.

However, the focus on crime rates matters when discussing the relative criminality of different groups and evaluating whether immigrants bring more crime than they add people to the United States.

Cuccinelli’s statement that crime rates don’t matter, that only the number of crimes matters, says nothing substantive about the potential danger that immigrants pose to Americans. Let me give an example. Under Cuccinelli’s interpretation, a city with 100 murders is twenty times more dangerous than a city with five murders. But if the city with 100 murders has a million residents and the city with five murders has only 100 residents, then the city with fewer murders is far more dangerous to the residents. The city with one million residents and 100 murders has a homicide rate of 10 per 100,000. The city with 100 residents and five murders has a homicide rate of 5,000 per 100,000, which is 500 times as great as the larger city with 20 times the number of murders.

This is an extreme example, but an example necessary to explain why crime rates are more important to understand relative to criminality and danger than the number of crimes. Which city would you want to live in?

Now, in that example, assume that 100,000 immigrants with a homicide rate 20 percent below that of the resident population move to the city with one million residents. Because the immigrants are less likely to commit homicide than the longer‐​settled residents of the city, the homicide rate drops from 10 per 100,000 to 9.8 per 100,000, but there are eight more murders. The city got slightly safer because the increase in the population was greater than the increase in the number of murders.

That example above makes the impact of immigration on crime seem even more dangerous than it likely really is. According to crime data from 2022, 79 percent of murder victims knew their murderers where investigators knew the prior relationship. Almost half of those pre‐​existing relationships were familial or sexual, the other half were neighbors, friends, acquaintances, employer/​employee, or a different relationship. Because families tend to be either mostly immigrants or mostly native‐​born Americans, and they live in different parts of the city near other similar people and tend to have friends and acquaintances who are similar—including more likely to have the same immigration status—it’s reasonable to infer that most of those eight extra homicide victims were probably also immigrants.

That doesn’t make their crimes any less heinous, but it does tell you that the non‐​immigrants in the city probably face even less danger than described in the previous paragraph.

A real‐​world example may help explain why the focus on crime rates is more important than the number of crimes. From 1970 to 2023, the number of homicides in Detroit dropped from 495 to 252, a 49 percent decrease. Whereas somebody who shared Cuccinelli’s opinion would say that this is a significant improvement, the homicide rate rose from 33 per 100,000 in 1970 to 41 per 100,000 in 2023, a 24 percent increase. The murder rate increased even though the number of murders fell because Detroit’s population fell even more from over 1.5 million in 1970 to about 620,000 in 2023—a decrease of 59 percent. If you consider only murder, Detroit is a more dangerous city today than in 1970.

Focusing on crime rates rather than the number of crimes is essential to compare criminality between populations such as immigrants and native‐​born Americans. Otherwise, there is no basis for arguing that one or the other is more criminally inclined, which really matters when discussing public safety. Additionally, we couldn’t judge whether crime differs between geographical regions or over time without looking at crime rates because the number of crimes generally goes up with the population in a cross‐​section and over the long run (with some significant variation). It’s trivially easy to point to crimes committed by a member of any large population no matter how one defines it, but doing so doesn’t reveal much useful information.

What comparative crime rates reveal is that more intensive enforcement of immigration laws aimed at all illegal immigrants, not just those convicted of violent or property crimes, will not make Americans safer on average. The result would be higher crime rates, ceteris paribus.

An increase in the number of crimes does not mean that a society is becoming more dangerous if the population grows even more. Similarly, a decrease in the number of crimes will not signify an improvement in safety if the population falls even more. It would be a better outcome if the number of crimes falls along with the crime rate as the population increases.

Furthermore, nothing above is meant to diminish the harm, pain, and anguish felt by victims of crime no matter who the criminal is. Criminals should be punished and, if they are non‐​citizens, deported from the United States after serving time in prison. However, it’s clear that we have a long and arduous debate ahead of us over immigration and crime if people with strong opinions on one side, like Cuccinelli, think that “[c]rime rates do not matter.”"