The Experiment Societyexperimentsociety.org⌕Get involved
Public SafetyTargetingPositive

LEAD — Law Enforcement Assisted Diversion (Seattle)

Seattle Police Department / King County Prosecuting Attorney / Public Defender Association / Vera Institute / University of Washington evaluation · Seattle, Washington, USA · 2011

Summary

LEAD (Law Enforcement Assisted Diversion) is one of the most influential criminal-legal-system innovations of the past 15 years. The Seattle pilot demonstrated that police officers, with appropriate training and a functioning case-management partner, can serve as a portal into social services rather than into the criminal-legal pipeline — for the specific subset of offenses where the underlying behavior is driven by addiction, mental illness, or extreme poverty. The Seattle evaluation's most important contribution was establishing that the model could produce both better individual outcomes and lower system costs, removing the false choice between 'tough on crime' and 'fiscally responsible' framings. The model has subsequently been replicated dozens of times, with results highly contingent on implementation. Where local case-management capacity is strong and police partnership is genuine, the Seattle effects have largely held; where either is weak, effects diminish substantially. The LEAD experience is also methodologically important: it demonstrated that quasi-experimental designs with careful matching can produce decision-grade evidence in criminal-justice contexts where RCT designs face severe ethical and political obstacles.

Research question

"Does pre-arrest diversion of low-level drug and prostitution offenders into community-based case management — rather than booking and prosecution — reduce subsequent criminal recidivism, improve housing and employment outcomes, and lower overall criminal-legal system costs?"

Methodology

Intervention

Police officers in designated Seattle neighborhoods could divert eligible individuals (low-level drug possession or sales for subsistence; prostitution) into the LEAD program at the point of contact, rather than booking them. Diverted individuals were connected to case managers who arranged housing, treatment, benefits enrollment, and other services on a harm-reduction (rather than abstinence-required) framework. No criminal charges were filed if engagement was maintained.

Assignment

Quasi-experimental — propensity score matching of LEAD participants to comparable individuals booked under standard procedures in the same neighborhoods; supplementary analyses using the program's geographic eligibility boundaries as identification

Sample size

Approximately 320 LEAD participants in the initial evaluation cohort; matched comparison group of 280 system-as-usual individuals

Primary outcome

Subsequent felony arrests and convictions; housing status; employment; receipt of legitimate income (benefits or earnings)

Effect estimate

LEAD participants were 39% less likely than matched comparisons to be arrested for new felonies in the two-year follow-up window; 87% more likely to obtain housing; and significantly more likely to be receiving income from legitimate sources. System-cost savings (averted jail nights, prosecution, court costs) modestly exceeded program costs.

Decision

LEAD has been replicated in 60+ US jurisdictions (Albany NY, Santa Fe, San Francisco, Atlanta, Baltimore, Portland OR, Phoenix, and many others) and has informed similar pre-arrest diversion models internationally. The model has been endorsed by the US Department of Justice and incorporated into the Bureau of Justice Assistance grant programs. Long-term effectiveness across implementations has been uneven — quality of case management is the recurring make-or-break variable.

Result

Positive

LEAD participants were 39% less likely than matched comparisons to be arrested for new felonies in the two-year follow-up window; 87% more likely to obtain housing; and significantly more likely to be receiving income from legitimate sources. System-cost savings (averted jail nights, prosecution, court costs) modestly exceeded program costs.

Evidence strength

Moderate

Quasi-experimental design with replication support.

Replication status

Replicated

Institution

Seattle Police Department / King County Prosecuting Attorney / Public Defender Association / Vera Institute / University of Washington evaluation

Location

Seattle, Washington, USA

Year

2011

Policy area

Public Safety

Mechanism

Targeting

More from these institutions

Other trials of this mechanism

Cite this entry

Seattle Police Department / King County Prosecuting Attorney / Public Defender Association / Vera Institute / University of Washington evaluation. (2011). LEAD — Law Enforcement Assisted Diversion (Seattle). The Experiment Society Registry. Retrieved from https://www.experimentsociety.org/registry/lead-seattle (primary report: https://leadbureau.org/wp-content/uploads/2020/03/Seattle-LEAD-Evaluation-Report-2017.pdf)

Citation network

Cited by 2 other entries in the registry

Cross-references

Adjacent experiments — same domain, parallel pilots, or alternative mechanisms.

Related experiments

Minneapolis, MN, USA · 2019

Minneapolis Foot Patrol Experiment

Positive

Washington, DC, USA · 2016

Body-Worn Camera RCT — Washington DC

Null

Philadelphia, USA · 2009

Philadelphia Foot Patrol Experiment

Positive

← Back to registryWhat the evidence shows →