Economist John R. Lott Jr. of the Crime Prevention Research Center released a working paper in which he purports to find that illegal immigrants in Arizona from 1985 through 2017 have a far higher prison admissions rate than U.S. citizens. Media from Fox News to the Washington Times and the Arizona Republic have reported on Lott’s claims while Attorney General Jeff Sessions and Representative Paul Gosar (R-AZ) have echoed them from their positions of authority. However, Lott made a small but fatal error that undermines his finding.
Lott wrote his paper based on a dataset he obtained from the Arizona Department of Corrections (ADC) that lists all admitted prisoners in the state of Arizona from 1985 to 2017. According to Lott, the data allowed him to identify “whether they [the prisoners] are illegal or legal residents.” This is where Lott made his small error: The dataset does not allow him or anybody else to identify illegal immigrants.[i]
The variable that Lott focused on is “CITIZEN.” That variable is broken down into seven categories. Lott erroneously assumed that the third category, called “non-US citizen and deportable,” only counted illegal immigrants. That is not true, non-US citizen and deportable immigrants are not all illegal immigrants. A significant proportion of non-U.S. citizens who are deported every year are legal immigrants who violate the terms of their visas in one way or the other, frequently by committing crimes. According to the American Immigration Council, about 10 percent of people deported annually are Lawful Permanent Residents or green card holders—and that doesn’t include the non-immigrants on other visas who were lawfully present in the United States and then deported. I will write more about this below.
Lott mistakenly chose a variable that combines an unknown number of legal immigrants with an unknown number of illegal immigrants. Lott correctly observed that “[l]umping together documented and undocumented immigrants (and often naturalized citizens) may mean combining very different groups of people.” Unfortunately, the variable he chose also lumped together legal immigrants and illegal immigrants.