Introduction

Efforts are underway across the United States to reduce the population of individuals in our jails and prisons, such as through mental health diversion programs. Mental health diversion programs are now among the most common interventions for individuals with mental health problems who come into contact with the criminal justice system. Briefly, these programs divert individuals with mental health problems from traditional case processing into community-based behavioral health treatment and alternative case processing. The Sequential Intercept Model describes the points of interception or opportunities for diversion across multiple stages of case processing, from initial police contact (pre-booking) through court appearance (post-booking) through sentencing (post-conviction) and, even, re-entry.¹ There are now hundreds of mental health jail diversion programs in operation across the United States,² including over 400 mental health courts.³ We focus herein on post-booking mental health jail diversion programs, including but not limited to mental health courts.

Increasingly, and not without controversy, risk assessment tools are being discussed as one strategy that may be used to support criminal justice reforms and alternatives to traditional case processing, including mental health jail diversion programs.^4–6 Risk assessment can be defined as the process of estimating the likelihood of future adverse outcomes. In the context of mental health jail diversion programs, the adverse outcome of interest is typically danger or threat to public safety (although the specific definition differs across jurisdictions and programs). Eligibility criteria for participation in mental health jail diversion programs, whether formally written in statute or otherwise, specify that for individuals with mental health problems to be diverted from the criminal justice system to alternative settings, including the community, they should not pose an unreasonable threat to public safety (see, for example, California Assembly Bill 1810). In other words, an individual should not be diverted from the criminal justice system to the community to the detriment of public safety.⁷

Traditionally, assessments regarding an individual’s threat to public safety – and thus, eligibility for diversion or other alternative to incarceration programs – are made by judges based on the facts of the case, official records, and any other information presented in court.⁸ This approach to risk assessment can be described as unstructured professional judgment because there is no validated checklist or protocol guiding what information should be considered and how this information should be combined or weighted to estimate threat to public safety. Instead, judges and other assessors relied on their professional training and experience to guide their identification, integration, and consideration of information to estimate an individual’s risk to public safety. However, on average, unstructured risk assessments are both less accurate and less consistent than those completed using structured risk approaches.^9–11 The use of risk assessment tools also can lead to better public safety outcomes.^12–15 The use of risk assessment tools, then, may help improve decisions regarding an individual’s appropriateness and eligibility for mental health jail diversion as a function of their estimated threat to public safety and the resources that would be required to mitigate that level of risk.⁷ Their use in mental health jail diversion programs also may contribute to improved individual and public safety outcomes.

In this paper, we first describe the process and components of risk. We then consider the use of risk assessment tools in mental health jail diversion programs. In doing so, our goal is to provide an overview of the science and practice of risk assessment to inform decision-making and risk mitigation in the context of mental health jail diversion programs.