Assessing Risk-Based Policies for Pretrial Release and Split Sentencing in Los Angeles County Jails.

Court-mandated downsizing of the CA prison system has led to a redistribution of detainees from prisons to CA county jails, and subsequent jail overcrowding. Using data that is representative of the LA County jail system, we build a mathematical model that tracks the flow of individuals during arraignment, pretrial release or detention, case disposition, jail sentence, and possible recidivism during pretrial release, after a failure to appear in court, during non-felony probation and during felony supervision. We assess 64 joint pretrial release and split-sentencing (where low-level felon sentences are split between jail time and mandatory supervision) policies that are based on the type of charge (felony or non-felony) and the risk category as determined by the CA Static Risk Assessment tool, and compare their performance to that of the policy LA County used in early 2014, before split sentencing was in use. In our model, policies that offer split sentences to all low-level felons optimize the key tradeoff between public safety and jail congestion by, e.g., simultaneously reducing the rearrest rate by 7% and the mean jail population by 20% relative to the policy LA County used in 2014. The effectiveness of split sentencing is due to two facts: (i) convicted felony offenders comprised ≈ 45% of LA County's jail population in 2014, and (ii) compared to pretrial release, split sentencing exposes offenders to much less time under recidivism risk per saved jail day

For each of the four options for split sentencing in the right column of Table 1, the optimal (i.e., optimizing over the remaining 16 options in Table 1) tradeoff curves of the annual rearrest rate vs.

<p><b>(a)</b> the mean jail population and <b>(b)</b> mean jail overcrowding. The circle denotes the status quo policy for LA County in early 2014.</p

A depiction of the process flow.

<p>The two key decisions (dotted lines) are whether to offer pretrial release (denoted by PTR?) and split sentencing (SS?), where the latter is available only to felons. The key tradeoff is between public safety, as measured by recidivism (dashed lines), and jail population, which is the total number of inmates waiting for arraignment, in pretrial custody or serving a post-sentence jail term. Each arrival has a charge type (non-felony or felony) and a CSRA risk category (low, medium or high), and some of the routing probabilities and time durations are functions of charge type, risk category and/or pretrial status (release or custody).</p

For each of the four tradeoff curves in Fig 2a, the optimal policy along the different points on the curve.

<p>Each policy is denoted by a pair of numbers, where the first number corresponds to the pretrial release for non-felonies (left column of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144967#pone.0144967.t001" target="_blank">Table 1</a>) and the second number corresponds to the pretrial release for felonies (middle column of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144967#pone.0144967.t001" target="_blank">Table 1</a>).</p