From the abstract for A National Study of Immigration Detention in the United States, Southern California Law Review, 2018, by Emily Ryo and Ian Peacock:
Amidst growing reports of abuses and rights violations in immigration detention, the Trump administration has sought to expand the use of immigration detention to facilitate its deportation policy. This study offers the first comprehensive empirical analysis of U.S. immigration detention at the national level. Drawing on administrative records and geocoded data pertaining to all noncitizens who were detained by U.S. Immigration and Customs Enforcement in fiscal year 2015, we examine who the detainees are, where they were held, and what happened to them. The bulk of the detained population consisted of men (79 percent) and individuals from Mexico, El Salvador, Guatemala, and Honduras (together, 89 percent). Over 59,000, or about 17 percent, of the detainees were juveniles under the age of eighteen. All states in the United States had one or more facility, with Texas and California having the highest number of facilities and detainees. Detention in privately operated facilities and in remote locations was common. We analyze three key detention outcomes: detention length, inter-facility transfers, and facility-related grievances. The average detention length for adults released in fiscal year 2015 was 38 days, though tens of thousands were detained for many months or years. A majority of these detainees experienced one or more inter-facility transfers, many involving movements across cities, states, and federal judicial circuits. In fiscal year 2015, the Detention Reporting and Information Line received over 48,800 facility-related grievances, a majority of which concerned issues pertaining to access to legal counsel and basic immigration case information. We find that detention outcomes vary significantly across facility operator types (private versus non private) and facility locations (within or outside of major urban areas). Specifically, our multivariate regression analyses show that confinement in privately operated facilities is associated with significantly longer detention and a higher number of grievances. We find a similar pattern of results for confinement in facilities located outside of major urban areas. On the other hand, confinement in privately operated facilities, and confinement in facilities located outside of major urban areas, respectively, are associated with lower risks of inter-facility transfers. These findings provide an important foundation for ongoing public discourse and policy discussions on the expanded use of detention as an immigration enforcement strategy.