Cato scholars have since published numerous Immigration Research and Policy Briefs to shed light on this topic. Michelangelo Landgrave, a doctoral student in political science at the University of California, Riverside, and I released a paper today that estimates that illegal immigrant incarceration rates are about half those of native-born Americans in 2017. In the same year, legal immigrant incarceration rates are then again half those of illegal immigrants. Those results are similar to what Landgrave and I published for the years 2014 and 2016. We estimated illegal immigrant incarceration rates by using the same residual method that demographers use to estimate the number of illegal immigrants in the United States, only we also applied that method to the prison population. We used the same method to also find that the incarceration rate for young illegal immigrants brought here as children and theoretically eligible for deferred action is slightly below those of native-born Americans.
The second strand of research from Cato looks at criminal conviction rates by immigration status in the state of Texas. Unlike every other state, Texas keeps track of the immigration statuses of convicted criminals and the crimes that they committed. Texas is a wonderful state to study because it borders Mexico, has a large illegal immigrant population, is a politically conservative state governed by Republicans, had no jurisdictions that limited its cooperation with federal immigration enforcement in 2015, and it has a law and order reputation for strictly enforcing criminal laws. If anything, Texas is more serious about enforcing laws against illegal immigrant criminals than other states. But even here, illegal immigrant conviction rates are about half those of native-born Americans – without any controls for age, education, ethnicity, or any other characteristic. The illegal immigrant conviction rates for homicide, larceny, and sex crimes are also below those of native-born Americans. The criminal conviction rates for legal immigrants are the lowest of all.
https://www.cato.org/blog/illegal-immigrants-crime-assessing-evidence