Washington State Institute for Public Policy
Jail diversion programs for offenders with mental illness (post-arrest programs)
Adult Criminal Justice
Benefit-cost estimates updated December 2016.  Literature review updated March 2015.
Jail diversion programs redirect mentally ill offenders from traditional criminal justice pathways to mental health treatment programs. The level of treatment afforded to mentally ill offenders can range from referrals to more substantial programs that integrate the criminal justice system and community-based providers in treating and monitoring offenders. This review focuses on post-arrest or post-booking diversion programs, which are jail- or court-based programs. Jail- and court-based diversion programs typically offer probation, deferred prosecution, or withdrawal of charges in lieu of incarceration for mentally ill offenders; these lesser punishments are often, although not always, dependent on treatment attendance. Note that this review does not include mental health courts or pre-arrest programs such as Crisis Intervention Teams, which were both reviewed separately.
The estimates shown are present value, life cycle benefits and costs. All dollars are expressed in the base year chosen for this analysis (2015). 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 ($3,760) Benefits minus costs $10,661
Participants ($3,040) Benefit to cost ratio n/a
Others ($3,026) Chance the program will produce
Indirect $14,869 benefits greater than the costs 61 %
Total benefits $5,044
Net program cost $5,618
Benefits minus cost $10,661
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
Benefits from changes to:1 Benefits to:
Taxpayers Participants Others2 Indirect3 Total
Crime $178 $0 $343 $90 $612
Labor market earnings associated with alcohol abuse or dependence ($2,211) ($4,869) $0 ($68) ($7,148)
Health care associated with alcohol abuse or dependence ($192) ($34) ($182) ($94) ($502)
Property loss associated with alcohol abuse or dependence $0 ($8) ($14) $0 ($22)
Labor market earnings associated with illicit drug abuse or dependence $1,079 $2,377 $0 $13,441 $16,897
Health care associated with illicit drug abuse or dependence $537 $93 $482 $270 $1,382
Health care associated with emergency department visits ($3,152) ($599) ($3,655) ($1,573) ($8,980)
Adjustment for deadweight cost of program $0 $0 $1 $2,804 $2,805
Totals ($3,760) ($3,040) ($3,026) $14,869 $5,044
Detailed Annual Cost Estimates Per Participant
Annual cost Year dollars Summary
Program costs ($5,603) 2014 Present value of net program costs (in 2015 dollars) $5,618
Comparison costs $0 2014 Cost range (+ or -) 10 %
Diversion costs are estimated from WSIPP’s analysis of Washington State daily jail costs assuming diverted offenders spend 30 days in jail on average compared to about 77 days for the non-diverted comparison group. This estimate is based on Washington average jail sentence based on Sentencing Guidelines Commission data for misdemeanor crimes with our estimated reductions for behavior. We also estimated supervision costs for the diverted offenders during those 15 days using Washington’s daily supervision rate based on data from the Department of Corrections. We estimated mental health treatment costs from Cowell et al. (2004). We examined alternative scenarios where diverted offenders spent only 15 days in jail and found no substantial difference in the results. 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.
Estimated Cumulative Net Benefits Over Time (Non-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 non-discounted dollars to simplify the “break-even” point from a budgeting perspective. 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.

Meta-analysis is a statistical method to combine the results from separate studies on a program, policy, or topic in order to estimate its effect on an outcome. WSIPP systematically evaluates all credible evaluations we can locate on each topic. The outcomes measured are the types of program impacts that were measured in the research literature (for example, 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.

Adjusted effect sizes are used to calculate the benefits from our benefit cost model. WSIPP may adjust effect sizes based on methodological characteristics of the study. For example, we may adjust effect sizes when a study has a weak research design or when the program developer is involved in the research. The magnitude of these adjustments varies depending on the topic area.

WSIPP may also adjust the second ES measurement. Research shows the magnitude of some effect sizes decrease 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. We also report the unadjusted effect size to show the effect sizes before any adjustments have been made. More details about these adjustments can be found in our Technical Documentation.

Meta-Analysis of Program Effects
Outcomes measured Primary or secondary participant No. of effect sizes Treatment N Adjusted 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 5 398 -0.019 0.072 36 -0.019 0.072 46 -0.019 0.791
Illicit drug abuse or dependence 5 386 -0.029 0.133 36 -0.163 0.210 37 -0.029 0.826
Homelessness 5 388 0.000 0.120 36 0.000 0.120 37 0.000 1.000
Emergency department visits 5 386 0.209 0.201 36 0.495 0.122 37 0.209 0.299
Alcohol abuse or dependence 5 386 0.159 0.242 36 0.159 0.242 37 0.159 0.509
Psychiatric symptoms 5 389 -0.004 0.073 36 -0.004 0.073 37 -0.004 0.961
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.

For more information on the methods
used please see our Technical Documentation.