Jail Diversion Cost Simulation Model

Projecting the effects of jail diversion

We developed and tested a cost simulation model that projects the utilization, consumer outcomes, costs, and potential cost savings of jail diversion programs for justice-involved individuals with a mental illness and oftentimes a co-occurring substance use disorder.


Jail diversion programs can enhance public safety and improve access to care for those who need it. An HSRI-developed model helps counties assess the feasibility of a jail diversion program in their communities. 

Counties have used the model to develop detailed jail diversion implementation plans and budgets.

  • System Analysis
  • System Redesign
  • Cost Analysis

Strategic planning across systems

Effective recovery support for people with mental illness and substance use disorders often requires collaboration across public health and safety systems. Cross-system efforts—like jail diversion programs, which use community-based treatment as an alternative to traditional criminal case processing—can produce powerful results, but planning and implementation can be challenging given the many agencies and their multiple historical approaches. 

HSRI developed a computerized model to project the fiscal and consumer outcome implications of a jail diversion program across systems. Using the model, communities can gauge the impact of a local program for different populations in terms of: 

  • Jail days
  • Functional level improvement
  • Cost by system

In addition to:

  • Hospital days
  • ER use
  • Units and costs for all services
  • Total cost and population by month

Benefitting from simulations

Simulation models can be a powerful decision-making tool. They’re a cheaper, quicker, safer, and scientifically sound alternative to costly studies. And they allow a community to consider the impact of various scenarios and service packages before they decide to adopt or implement. 

Our model combines expert judgment with real-world, local data to produce tailored projections. Jurisdictions can enter specifics for their potential program, including:

  • Number of cases they can divert per month by mental health status and criminal justice charges
  • Mental health and substance abuse services the diverted group should receive in the community
  • Costs of services in the mental health system
  • Criminal justice costs associated with each offense

Results and Findings

Our model was tested using potential jail diversion candidates from two communities: Chester County, Pennsylvania and Travis County, Texas. 

Our test simulation showed that, in both the short term and long term, costs are shifted from the criminal justice system to the community mental health system—but the long-term trend is cost avoidance as individual service needs lessen over time and recidivism rates are reduced. 

We also found that:

  • Jail diversion interventions alone may reduce jail days, but other desired outcomes depend on access to appropriate behavioral health services in the community 
  • It takes time for a jail diversion program to become cost effective in a system providing appropriate service packages – as little as two years to four or more depending on the scenario
  • To improve the likelihood of cost scenarios that favor jail diversion, programs need to include higher-level charges including felonies 
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According to a beta test of the model in Travis County, Texas, a jail diversion program would produce a cost savings in the second or third year, with savings varying based on the population chosen for diversion.

Substance Abuse and Mental Health Services Administration (SAMHSA)

Project Partner(s):

Policy Research Associates Inc.

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