Community Safety and Violence

Estimating the Impact of Alternative Crisis Response Models on Community Violence

This study will describe, estimate, and explore the effectiveness of community-centered safety models (CCSMs)-including co-response, alternative response, and community violence intervention modalities-implemented across U.S. municipalities to prevent community violence among youth and young adults (YYA). Specifically, the investigators will (1) describe CCSM implementation using implementation-science methods, (2) estimate CCSMs' impacts on community-violence outcomes using quasi-experimental methods, and (3) explore operational and contextual factors associated with stronger or weaker effects.

Study Overview

• Status: Recruiting
• Conditions: Community-Centered Safety

• Study Type: Observational
• Enrollment (Estimated): 15

Contacts and Locations

• Study Contact: Name: Bennett Allen, PhD; Phone Number: 646- 501-3708; Email: Bennett.Allen@nyulangone.org
• Study Contact Backup: Name: Brittany Griffin; Phone Number: 914-382-7292; Email: Brittany.Griffin@nyulangone.org

Study Locations

• United States
  • New York
    • New York, New York, United States, 10016
      • Recruiting
      • NYU Langone Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This protocol does not involve prospective enrollment or direct interaction with individuals. The "participants" in this study are:

1. Jurisdictions/sites (U.S. cities/counties) operating fully implemented community-centered safety models (CCSMs)-co-response, alternative response, or community violence intervention; and
2. Community populations within those jurisdictions, represented only through secondary, de-identified or limited administrative datasets (e.g., violent deaths, nonfatal injury encounters, crime/arrest records) used for population-level analyses.

Youth and young adults (YYA; ~ages 10-34) are a focal analytic subgroup because they bear a disproportionate burden of community violence. No individuals are recruited, contacted, or intervened upon.

Description

Inclusion Criteria for Jurisdiction/Sites:

1. Intervention modality clarity: A single, identifiable CCSM-Co-Response (CRM), Alternative Response (ARM), or Community Violence Intervention (CVI)-implemented at city/county level.
2. Documented launch date & scope: Public or official documentation specifying program start date, catchment, operating hours, staffing, eligibility, and core activities.
3. Observation window: ≥24 months pre-implementation and ≥12 months post-implementation of outcome data (monthly preferred; annual acceptable for fatal outcomes).
4. Outcomes coverage: Availability of primary outcomes (fatal and nonfatal violent injury) and at least one secondary justice outcome at the jurisdiction level.
5. Data quality: Stable geographic boundaries, consistent reporting practices, and no catastrophic breaks that preclude credible counterfactual fit.
6. Donor comparability: Jurisdiction characteristics and data cadence compatible with a pooled augmented synthetic control design (i.e., can be matched to a synthetic control and included in permutation tests).

Exclusion Criteria:

1. Pilot-only or indeterminate programs: Short-lived pilots, ambiguous or multi-modality rollouts where treatment timing or content cannot be reliably defined.
2. Severe data discontinuity: Major boundary changes, reporting suspensions, coding overhauls, or dataset gaps that undermine time-series integrity (e.g., prolonged outages during system migration) and cannot be addressed with standard remedies.
3. Overlapping major interventions: Concurrent, poorly measured citywide initiatives (e.g., sweeping policy bundles) that coincide with the CCSM start and make identification infeasible.
4. Insufficient pre-period: <24 months pre-implementation data for primary outcomes.
5. Incompatible cadence/aggregation: Outcomes only available at spatial or temporal units that cannot be aligned with other sites or donors.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
U.S. Cities/Counties; Approximately 15 U.S. cities/counties (≈5 per CCSM modality) selected for evaluability.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Homicide Rate	Measured as deaths per 100,000 (annual).	Baseline, Month 36
Firearm Homicide Rate	Measured as deaths per 100,000 (annual).	Baseline, Month 36
Assault-related ED & inpatient encounters (combined) rate	Measured as visits/admissions per 10,000 (monthly).	Baseline, Month 36
Firearm-assault-related ED & inpatient encounters (combined) rate	Measured as hospitalizations per 10,000 (monthly).	Baseline, Month 36
Nonfatal firearm assault rate	Measured as hospitalizations per 10,000 (monthly).	Baseline, Month 36

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Aggravated assault arrest rate	Measured as arrests per 10,000 (monthly).	Baseline, Month 36
Weapons-related arrest rate	Measured as arrests per 10,000 (monthly).	Baseline, Month 36
Robbery arrest rate	Measured as arrests per 10,000 (monthly).	Baseline, Month 36
Juvenile arrest rate	Measured as arrests per 10,000 juveniles (monthly).	Baseline, Month 36

Collaborators and Investigators

• Sponsor: NYU Langone Health
• Collaborators: Centers for Disease Control and Prevention
• Investigators: Principal Investigator: Bennett Allen, PhD, NYU Langone Health

Study record dates

Study Major Dates

• Study Start (Actual): September 30, 2025
• Primary Completion (Estimated): September 29, 2028
• Study Completion (Estimated): September 29, 2028

Study Registration Dates

• First Submitted: March 20, 2026
• First Submitted That Met QC Criteria: March 20, 2026
• First Posted (Actual): March 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 27, 2026
• Last Update Submitted That Met QC Criteria: March 20, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 25-01382; R01CE003770 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No