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Washington State Institute for Public Policy
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Jail diversion (post-arrest)

Adult Criminal Justice
Benefit-cost methods last updated December 2024.  Literature review updated April 2025.
Jail diversion programs divert individuals from the traditional criminal legal system (CLS) after they have been arrested and booked into jail but before significant progression through the CLS. Programs typically target specific populations for diversion, including those with untreated mental health or substance use disorders or low-level offenders. Diverted individuals are generally linked to treatment and/or mandated to complete program elements such as education, counseling, or community service. Program duration varies, ranging from short-term programming to about six months of services. Pre-arrest diversion programs and mental health courts were reviewed separately from this meta-analysis.
 
ALL
BENEFIT-COST
META-ANALYSIS
CITATIONS
For an overview of WSIPP's Benefit-Cost Model, please see this guide. The estimates shown are present value, life cycle benefits and costs. All dollars are expressed in the base year chosen for this analysis (2023).  The chance the benefits exceed the costs are derived from a Monte Carlo risk analysis. The details on this, as well as the economic discount rates and other relevant parameters are described in our Technical Documentation.
Benefit-Cost Summary Statistics Per Participant
Benefits to:
Taxpayers $2,707 Benefits minus costs $10,836
Participants ($382) Benefit to cost ratio n/a
Others $4,948 Chance the program will produce
Indirect $2,395 benefits greater than the costs 95%
Total benefits $9,668
Net program cost $1,168
Benefits minus cost $10,836

^WSIPP’s benefit-cost model does not monetize this outcome.

^^WSIPP does not include this outcome when conducting benefit-cost analysis for this program.

Meta-analysis is a statistical method to combine the results from separate studies on a program, policy, or topic to estimate its effect on an outcome. WSIPP systematically evaluates all credible evaluations we can locate on each topic. The outcomes measured are the program impacts measured in the research literature (for example, impacts on crime or educational attainment). Treatment N represents the total number of individuals or units in the treatment group across the included studies.

An effect size (ES) is a standard metric that summarizes the degree to which a program or policy affects a measured outcome. If the effect size is positive, the outcome increases. If the effect size is negative, the outcome decreases. See Estimating Program Effects Using Effect Sizes for additional information on how we estimate effect sizes.

The effect size may be adjusted from the unadjusted effect size estimated in the meta-analysis. Historically, WSIPP adjusted effect sizes to some programs based on the methodological characteristics of the study. For programs reviewed in 2024 or later, we do not make additional adjustments, and we use the unadjusted effect size whenever we run a benefit-cost analysis.

Research shows the magnitude of effects may change over time. For those effect sizes, we estimate outcome-based adjustments, which we apply between the first time ES is estimated and the second time ES is estimated. More details about these adjustments can be found in our Technical Documentation.

Meta-Analysis of Program Effects
Outcomes measured Treatment age No. of effect sizes Treatment N Effect sizes (ES) and standard errors (SE) used in the benefit-cost analysis Unadjusted effect size (random effects model)
First time ES is estimated Second time ES is estimated
ES SE Age ES SE Age ES p-value
Crime
Involvement in the criminal justice system (e.g., arrests, charges, convictions, incarceration) measured through administrative records (e.g. court records, arrests) or self-report.
 32 6 13618 -0.162 0.045 33 -0.162 0.045 41 -0.162 0.001
Alcohol use disorder
Clinical diagnosis of alcohol use disorder or symptoms measured on a validated scale.  
 32 5 386 0.156 0.241 32 0.000 0.187 35 0.156 0.518
Illicit drug use disorder
Clinical diagnosis of illicit drug use disorder or symptoms measured on a validated scale. When possible, we exclude cannabis/marijuana use disorder from this outcome.
 32 5 386 -0.044 0.133 32 0.000 0.187 35 -0.044 0.741
Psychiatric symptoms^
Mental health symptoms (such as symptoms of psychosis) in individuals with serious mental illness, measured on a validated scale.
 32 5 388 0.025 0.073 32 n/a n/a n/a 0.025 0.731
Death^^
“All-cause mortality,” or the proportion of all deaths in a given population during a specified period of time, regardless of the cause.
32 1 11232 -0.174 0.083 32 -0.174 0.083 32 -0.174 0.035
Emergency department visits
Whether someone visited the emergency department, or the number of times they visited the emergency department.
32 6 11618 0.162 0.147 32 0.000 0.086 34 0.162 0.271
Hospitalization
Hospital admission, for any reason.
 32 1 11232 0.030 0.017 32 0.000 0.000 33 0.030 0.085
Homelessness^
A lack of stable housing, often measured through self-report of conditions like living on streets or in shelters in a given time period.
 32 5 388 -0.087 0.142 32 n/a n/a n/a -0.087 0.540
1In addition to the outcomes measured in the meta-analysis table, WSIPP measures benefits and costs estimated from other outcomes associated with those reported in the evaluation literature. For example, empirical research demonstrates that high school graduation leads to reduced crime. These associated measures provide a more complete picture of the detailed costs and benefits of the program.

2“Others” includes benefits to people other than taxpayers and participants. Depending on the program, it could include reductions in crime victimization, the economic benefits from a more educated workforce, and the benefits from employer-paid health insurance.

3“Indirect benefits” includes estimates of the net changes in the value of a statistical life and net changes in the deadweight costs of taxation.
Detailed Monetary Benefit Estimates Per Participant
Affected outcome: Resulting benefits:1 Benefits accrue to:
Taxpayers Participants Others2 Indirect3 Total
Crime Criminal justice system $2,858 $0 $4,973 $1,429 $9,259
Alcohol use disorder Labor market earnings associated with alcohol abuse or dependence ($192) ($452) $0 $0 ($644)
Property loss associated with alcohol abuse or dependence $0 ($2) ($3) $0 ($5)
Mortality associated with alcohol ($1) ($2) $0 ($70) ($74)
Illicit drug use disorder Labor market earnings associated with illicit drug abuse or dependence $27 $64 $0 $0 $91
Health care associated with illicit drug abuse or dependence $104 $16 $106 $52 $277
Mortality associated with illicit drugs $7 $16 $0 $448 $470
Hospitalization Health care associated with general hospitalization ($27) ($1) ($26) ($13) ($67)
Emergency department visits Health care associated with emergency department visits ($69) ($19) ($101) ($34) ($223)
Program cost Adjustment for deadweight cost of program $0 $0 $0 $584 $584
Totals $2,707 ($382) $4,948 $2,395 $9,668
Click here to see populations selected
Detailed Annual Cost Estimates Per Participant
Annual cost Year dollars Summary
Program costs $1,171 2012 Present value of net program costs (in 2023 dollars) $1,168
Comparison costs $2,088 2012 Cost range (+ or -) 30%
Jail diversion costs are estimated using a combination of cost estimates from Cowell et al. (2004) and from WSIPP’s analysis of Washington State’s daily jail and supervision costs. We used the Washington average jail sentence, based on Sentencing Guidelines Commission data for misdemeanors, and our estimated reductions for behavior, to estimate that diverted individuals spend, on average, 47 days fewer in jail than non-diverted comparison group individuals. Treatment group costs therefore include the cost of supervision for 47 days of diverted jail time (based on WSIPP’s estimates of per person average daily community supervision costs), as well as the costs of services received by diverted individuals reported in Cowell et al. (2004). Comparison group costs for non-diverted individuals reflect the cost of 47 more days in jail relative to the diverted treatment group (based on WSIPP’s estimates of per person average daily jail cost). Cowell, A.J., Broner, N., & Dupont, R. (2004). The cost-effectiveness of criminal justice diversion programs for people with serious mental illness co-occurring with substance abuse: Four case studies. Journal of Contemporary Criminal Justice, 20(3), 292-314.
The figures shown are estimates of the costs to implement programs in Washington. The comparison group costs reflect either no treatment or treatment as usual, depending on how effect sizes were calculated in the meta-analysis. The cost range reported above reflects potential variation or uncertainty in the cost estimate; more detail can be found in our Technical Documentation.
Benefits Minus Costs
Benefits by Perspective
Taxpayer Benefits by Source of Value
Benefits Minus Costs Over Time (Cumulative Discounted Dollars)
The graph above illustrates the estimated cumulative net benefits per-participant for the first fifty years beyond the initial investment in the program. We present these cash flows in discounted dollars. If the dollars are negative (bars below $0 line), the cumulative benefits do not outweigh the cost of the program up to that point in time. The program breaks even when the dollars reach $0. At this point, the total benefits to participants, taxpayers, and others, are equal to the cost of the program. If the dollars are above $0, the benefits of the program exceed the initial investment.

Citations Used in the Meta-Analysis

Broner, N., Lattimore, P.K., Cowell, A.J., & Schlenger, W.E. (2004). Effects of diversion on adults with co-occurring mental illness and substance use: Outcomes from a national multi-site study. Behavior Sciences and the Law, 22(4), 519-541.

Davis, R.C., Reich, W.A., Rempel, M., & Labriola, M. (2021). A multisite evaluation of prosecutor-led pretrial diversion: Effects on conviction, incarceration, and recidivism. Criminal Justice Policy Review, 32(8), 890–909.

Weatherburn, D., Rahman, S., Todd, S., Poynton, S., Black, S., Merinda, T., & Farrell, M. (2025). The impact of a voluntary alcohol and other drug diversion program on reoffending, imprisonment, and health. International Journal of Drug Policy, 138.C3929