By now, most people paying attention to the U.S. criminal justice system have heard about problems with the overuse and misuse of local jails. Chief among these problems are the serious, even deadly, harms caused by even brief periods of jail detention. But one problem has escaped the attention of the public and policymakers alike: the unnecessary jail detention caused by “detainers,” which account for as much as one-third of some jail populations, if not more. This briefing explains how detainers (also often called “holds”) contribute to unnecessary jailing, and offers a preliminary analysis of available national, state, and local data as evidence of a widespread policy problem that demands greater attention.

Typically, people in jails are categorized as unconvicted (65% nationally) or convicted (35%). In our Mass Incarceration: The Whole Pie report, we have been able to go one step further, breaking apart the roughly 16% who are held for other agencies that pay to keep them boarded there. But another group of people are still obscured by this breakdown of the jail population: people who are in jail for more than one reason, who have what we’ll call a “dual status.” A significant number of people are locked up because of some kind of “detainer” or “hold” for their probation or immigration status, for example, which renders them ineligible for release. These people aren’t brought into jail on a detainer, but the detainer can keep them there when they otherwise could have gone home.

For example, if someone who is on probation is charged with a new low-level offense, they can be held in jail without bail if the probation department has issued a detainer for violating their probation. In fact, this is a critical part of Kalief Browder’s story: initially held on unaffordable bail, he was later denied bail because the Probation Department filed paperwork saying the new charge meant he had violated probation. It was the “violation of probation” – or “probation hold” – that kept Browder at Riker’s so long, causing irreparable harm that led to his eventual death. Without his dual status as a probationer, he probably wouldn’t have had money bail set in the first place: his friend, who was arrested along with him but was not on probation, was allowed to go home the next day. Even with his probation status, the judge was willing to set bail. It was only when the Probation Department stepped in to make their claim on his freedom that the judge remanded him without bail.

Read the full article about unnecessary jailing by Wendy Sawyer, Alexi Jones, and Maddy Troilo at Prison Policy Initiative.