Bryan Caplan
A high fraction of immigrants are young, low-skilled, Hispanic males. Given these demographics, I long assumed that immigrants would have relatively high crime rates. While I kept this problem in perspective, I took it for granted that increased crime was a genuine drawback of immigration.
I was wrong.
A fascinating NBER Working Paper (earlier, free version here) by Kristin Butcher and Anne Piehl shows that, despite their demographics, immigrants are drastically less criminal than native-born Americans. In fact, immigrants have one-fifth the incarceration rate of natives. Yes, natives are incarcerated at five times the rate of the foreign-born:
Using the 1980, 1990, and 2000 Censuses, we show that 18-40 year-old male immigrants have lower institutionalization rates than the native born in each year. The gap in these institutionalization rates widens over the decades, and by 2000 immigrants have institutionalization rates that are one-fifth of the native born.
more. . .
http://econlog.econlib.org/archives/2007/07/mea_culpa_how_i.html