Innovations in Violent Crime Reduction Strategies

IACP Annual MeetingsChicago, Illinois

October 28, 2019

Panelists

• Robin S. Engel, PhD, Professor, University of Cincinnati; Director, IACP/UC Center for Police Research and Policy

• Chief Michael Harrison, Baltimore Police Department

• Deputy Chief Chris Jones, Las Vegas Metro Police Department

• Ronal Serpas, Ph.D., Professor of Practice, Loyola University New Orleans

• Tamara Herold, Ph.D., Associate Professor, University of Nevada, Las Vegas

IACP / UC Center for Police Research and Policy (CPRP)

Our Mission: Bring Science to the Streets

• Provide police agencies with access to cutting-edge research, translated into actionable recommendations

• Conduct and facilitate police research; foster collaborative relationships between researchers and police agencies

o Answer urgent policing issues

o Drive sound policy

• Direct access to the field: Research driven by law enforcement, for law enforcement

IACP/ UC Center for Police Research and Policy

Sponsor: Arnold Ventures (formerly the Laura and John Arnold Foundation)

Translate existing research on topics that impact policy & practice• Use of Force • De-escalation Training• Implicit Bias Training• Arrest Decision Making / Alternatives to Arrest• Violence against Law Enforcement• Domestic Violence• First-line Supervision

Conduct large-scale research studies targeting critical issues• Implicit Bias Training (NYPD)• Gang Violence Reduction Strategies (Las Vegas Metro PD)• Use of Force (Tulsa PD and Cincinnati PD)• De-escalation Training (UCPD and Louisville Metro PD)• Case Closure Rates (Knoxville PD)• Reducing Domestic Violence (Tulsa PD)

Most Effective Evidence-Based Violence Reduction Strategies

1. Hot Spots Deployment

2. Focused Deterrence

3. Place Network Investigations

Jurisdiction segments

Intervention Focus

Deferred/Long-termLagged/IntermediateRapid/Short-term

Hot Spot Policing

Focused Deterrence

Place Network Investigations

Onset & Duration

Crime Impact

Complexity

Place Place

Social networks Crime infrastructure

X

X

X

X

X

Partnerships

Low High

Many

Medium

SeveralFew/None

Las Vegas Metro Hot Spots Strategy

Deployment of saturation patrols to specific locations that generate disproportionate amount of crime• 6 month cluster randomized controlled trial (Nov 2018 – Apr 2019)• Randomized 22 Treatment and 22 Control Street Segments• Treatment = patrol officers deployed (randomly via calls for service)

every day, for 2 hours of total exposure at each hot spot each day (15 minute intervals)• Treatment type also randomized: Stationary w/ lights, or Walk

• Control = business as usual• Treatment-to-control conditions geographically proximate (average 3

street segments apart; none within one block of each other)• Abutting segments used to measure possible immediate

displacement or diffusion of benefits

LVMPD Hot Spots and Control Map

Red=Treatment Blue= Control

Las Vegas Metro Hot Spots Strategy

Fidelity assessment indicates strong implementation consistent with research design

• Police-generated dispatches deploy officers to hot spots, and police action (walk or stationary/lights)

• Cleared calls (or late-responses) collected• Each hot spot designated 2 hours total patrolling per day for 6

months• 1.5 hours observed for 90% of all hot spots• 2 hours observed for 55% of all hot spots

Results (1): Hot Spots Strategy

• Treatment locations compared to controls during intervention period (Nov 2018 – Apr 2019)

o55% reduction in violent criminal offenses

o18% reduction in property criminal offenses

o52% reduction in violent calls for service

o12% reduction in property calls for service

Treatment areas (saturation patrols) = fewer CFS and reported criminal offenses (violence and property) compared to controls

Results (2): Hot Spots Strategy

Treatment effect varied by type of treatment

• Stationary with Lights = greatest impact on reducing violent CFS and violent offenses

• Park and Walk = greatest reductions on reducing property offenses

• No impact on property CFS for either type

Results (3): Hot Spots Strategy

• Treatment areas experienced small reductions, while control areas experienced large increases

• Either: (1) crime was going up (but deployment deterred increase in treatment areas), or (2) crime was displaced from treatment to control areas

• Additional analyses comparing treatment and control areas themselves pre/post intervention found slight displacement

BUT … possibility of displacement of crime to other areas detected

Findings Summary: Hot Spots Strategy

• Reduction was strongest for violence, marginal for property

• Stationary with lights had strongest impact on violence(offenses and CFS)

• Walking patrols had strongest impact on property offenses

• Possible crime displacement did occur; impact was slight

Hot spot deployment had strong effect, reducing CFS and reported crimes (property and violence)

Las Vegas Focused Deterrence Strategy

• Offender meetings with law enforcement, social services, and community support messages in May and Oct 2018

• 518 parolees randomized assigned to:• Offender notification meeting (treatment) or • Receive business as usual (control)

• Classified into 4 risk groups (low, low-moderate, mid-moderate, or high) prior to selection into treatment/control conditions

• Randomized Controlled Trial (RCT) designed to test impact solely of offender notification meetings, not full gang enforcement model

Classification TypePrior

Violent ArrestAffiliated w/ Violent Gang

Group 1: Low Risk

Group 2: Low-Moderate Risk

Group 3: Mid-Moderate Risk

Group 4:High Risk

Las Vegas Focused Deterrence StrategyRisk Classification based on: (1) prior violent arrest history, and (2) affiliation with violent gang

Offender Notification Meetings

• 216 probation/parolees assigned to attend meetings (treatment)

• 302 not assigned (control group)

• 1-2 match for lowest risk group; 1-1 match for other risk groups

• Approximately 75% of those assigned to meeting attended

• Messages delivered at meetings:• Law enforcement deterrent message• Social service and assistance-based message• Community message re: harm, impact, and support

Meetings with ~30 attendees conducted on May 8, May 15, and Oct 4, 2018

Classification TypePrior

Violent ArrestAffiliated w/ Violent Gang

Reduced Re-arrest?

Group 1: Low Risk

Group 2: Low-Moderate Risk

Group 3: Mid-Moderate Risk

Group 4:High Risk

Las Vegas Focused Deterrence Strategy

Risk Classification based on: (1) prior violent arrest history, and (2) affiliation with violent gang

Las Vegas Focused Deterrence Strategy:Findings

Probation/Parolees with no violent arrests but gang affiliated, were less likely to be re-arrested after attending notification meeting compared to others in same risk group who did not attend meeting

• 1 out of 4 in treatment group (attended meeting) were re-arrested

25% failure rate

• 2 out of 4 in control group (did not attend meeting) were re-arrested

50% failure rate

• With RCT design, bivariate relationship is strong – suggestive that non-violent individuals exposed to violent groups can be positively impacted by deterrence/social support messages

Offender notification meetings had positive impact on low-moderate risk group