The Department of Homeland Security (DHS) and the Department of Justice (DOJ) today released a report that found that about 94 percent of foreign-born inmates in Federal prisons are illegal immigrants. That is not surprising, as illegal immigrants convicted of an immigration offense are incarcerated in federal prison and account 7.3 percent of all inmates. Likewise, drug traffickers who cross international borders are also in federal prison and account 46.3 percent of all prisoners. Thus, illegal immigrants are overrepresented in federal prison because the federal government enforces immigration laws and many drug trafficking laws but only a small fraction of all those incarcerated for all crimes committed in the U.S. are in federal prisons. 

The authors of this DHS/DOJ report do deserve credit for highlighting its shortcomings. On the first page, it states:

This report does not include data on the foreign-born or alien populations in state prisons and local jails because state and local facilities do not routinely provide DHS or DOJ with comprehensive information about their inmates and detainees. This limitation is noteworthy because state and local facilities account for approximately 90 percent of the total U.S. incarcerated population.

The federal prison population is not representative of incarcerated populations on the state and local level, so excluding them from the report means that it sheds little light on nationwide incarcerations by nativity, legal status, or type of crime. On the last point, it is shocking how unrepresentative federal prison is regarding the types of crimes its inmates are convicted of. In 2016, 67,742 people were sentenced to federal prison. Almost 30 percent of them were for immigration offenses. Those immigration convictions comprised 100 percent of the convictions for immigration crimes in the United States in 2016. By contrast, there were only 85 federal convictions for murder out of a nationwide total of 17,785 murder convictions that year, comprising less than 0.5 percent of all murders.

If Garcia Zarate had actually been convicted of murdering Kate Steinle, then he would have been incarcerated in California state prison and he would not show up as an illegal immigrant murderer in this DHS/DOJ report. What good is a federal report on illegal immigrant incarceration rates if it would have excluded Kate Steinle’s killer had he been convicted? 

The DHS/DOJ report also explained why they did not include an estimate of illegal immigrants incarcerated on the state and local level:

DHS and DOJ are working to develop a reliable methodology for estimating the status of state and local incarcerated populations in future reports.

A March 2017 Cato Institute Immigration Research and Policy Brief employed a commonly used residual statistical methodology to analyze the incarcerated population in the U.S. Census for 2014. We found that illegal immigrants were about 44 percent less likely to be incarcerated than native-born Americans. I look forward to reviewing any methodology that the federal government comes up with but illegal immigrant criminals would have to be severely undercounted in prisons to give them an incarceration rate that even approaches native-born Americans. 

The broad finding among criminologists and economists who study this topic is that immigrants are less crime-prone than natives whether measured by the areas where they live or their incarceration rates. Although there is less research on illegal immigrant criminals, the general finding is that they are less crime-prone or about as criminally inclined as native-born Americans. The DHS/DOJ report reveals no new information about incarcerations on the federal level, does not provide evidence for a higher nation-wide illegal immigrant incarceration rate, nor does it support the administration’s plea for more border security.