75 % less youth violence in one Denver neighbourhood: what European communities can learn from the CTC evaluation

A study from Denver, Colorado, provides new empirical evidence on the effectiveness of Communities That Care (CTC) in preventing youth violence. The study by Kingston and colleagues (2026) also deepens our understanding of the conditions under which the approach succeeds, findings that matter for any European community considering it. The evaluation stands out for its methodological quality and its long observation period.

The study in detail: design and methods

Study design and areas

The study examined two violence-affected neighbourhoods in Denver with high rates of violence and socio-economic disadvantage:

• Neighbourhood A: a larger area with about 11 % of families below the poverty line.
• Neighbourhood B: a smaller area with 19 % of families in poverty.

At the start of the study both neighbourhoods had youth arrest rates well above the US national average, a starting point comparable to disadvantaged districts in the larger cities of Europe.

An innovative methodology

The researchers used two quasi-experimental approaches that are equally relevant for European evaluation studies.

1. Interrupted time series (ITS). This method compares trends before and after the intervention within the same neighbourhood. It answers the question: did the course of youth violence change significantly after CTC implementation began?

The ITS analysis showed:

• in neighbourhood A, no significant change in already low trends;
• in neighbourhood B, a significant reversal from rising to falling arrest rates.

2. Difference-in-differences (DiD) with synthetic controls. This method constructs a “synthetic control community” from the data of all other Denver neighbourhoods that resemble neighbourhood B in relevant characteristics. It addresses a common problem in prevention research: the absence of suitable control groups. The DiD analysis confirmed that the reduction in neighbourhood B was significantly larger than in comparable areas without CTC.

Primary outcome: youth arrests for violent offences

The study’s main indicator was youth arrests for violent offences among 10- to 24-year-olds, covering:

• murder and manslaughter;
• robbery;
• aggravated assault;
• rape.

For a European reader it is important to remember that an “arrest” in the US system is not the same event as in most European police systems, where the decisive record is usually the registration of a suspect rather than a custodial arrest. Comparable European indicators would be:

• police-recorded violent offences by young suspects, from national crime statistics;
• suspect counts by age group;
• convictions in the youth courts.

The intervention: a modified CTC with a community-level focus

Theoretical foundation: the Social Development Model

The Social Development Model underlying the study holds that young people are bonded to prosocial adults and institutions through three elements:

1. opportunities for prosocial involvement;
2. skills to take up those opportunities successfully;
3. recognition for prosocial participation.

These bonds foster the adoption of prosocial norms and reduce problem behaviour.

The strategies implemented

1. Power of One (PO1) media campaign. A youth-led media campaign with digital advertising, public events and social-media content, aimed at strengthening attachment to the neighbourhood.

2. Social Development Strategy (SDS). A systematic approach to embedding the three core elements – opportunities, skills, recognition – in all programme activities.

3. Violence, Injury Protection and Risk Screen (VIPRS). A screening instrument for paediatricians to identify young people at elevated risk of violence early. Some European early-help systems use similar screening at routine health contacts, linking health services with services for children and families.

4. Mini-grants for local initiatives (neighbourhood A only). Small grants, on average 2,095 US dollars, for local organisations to run youth-oriented activities.

5. PATHS and social-emotional learning across the neighbourhood (neighbourhood B only). “Promoting Alternative Thinking Strategies”, a social-emotional learning programme, delivered beyond schools across the whole neighbourhood. PATHS has been adapted and evaluated in several European countries, among them Croatia, the Netherlands, Switzerland and the United Kingdom, with results that vary by country and implementation; the evidence registers page shows where to look it up.

Central results: what the numbers mean

The mobilisation effect in neighbourhood B

A central result was the fall in the arrest rate in neighbourhood B from 1,086 per 100,000 young people in 2016 to 443 in 2017, a reduction of 59 % in the first year alone. This “mobilisation effect” suggests that the intensive preparation and community mobilisation can itself have a preventive effect.

Long-term effects and sustainability

By 2021 the rate in neighbourhood B had fallen further, to 276 per 100,000, an overall reduction of 75 %. The persistence of the effect over five years, and through the pandemic, points to a durable intervention and contradicts the criticism that prevention successes are only short-lived.

Neighbourhood A: no measurable effect, from a low baseline

Neighbourhood A showed no significant changes, but it had started from low values (an average of 312 per 100,000) because of an earlier round of CTC participation (2011–2016). The stability of those rates during the pandemic, when many US cities recorded rises in violence, can cautiously be read as holding a low level; it is not robust evidence of effect. The study’s finding of effect is therefore confined to neighbourhood B.

Success factors and obstacles: lessons for practice

The different results in the two neighbourhoods offer important insights into the conditions of successful prevention. The central difference between the two areas lay in their size and the implementation conditions that followed from it. Neighbourhood B, with roughly a quarter of the population of neighbourhood A, allowed a more intensive penetration of the prevention measures and more personal networking among the actors. That manageable size proved a decisive advantage for the successful mobilisation and lasting anchoring of the CTC system.

A further critical success factor in neighbourhood B was the pressure to act created by preceding violent events. That experience of crisis led to an exceptionally high level of mobilisation and a shared will to change. Combined with a clear leadership structure and committed local champions, it produced a focused implementation environment without competing initiatives, which allowed full concentration on CTC.

Neighbourhood A, by contrast, faced structural challenges that made renewed mobilisation difficult despite its earlier CTC experience. The sheer size of the area made area-wide implementation complex and resource-intensive. Multiple prevention initiatives were competing for attention and resources, leading to duplication and unclear responsibilities. At the same time, rapid social change through gentrification destabilised the networks that had grown up. After years of continuous programme participation, a certain “prevention fatigue” among key actors also dampened renewed commitment to CTC.

Transfer to Europe: what can we learn?

Methodological implications

The study shows that methodologically sound evaluation of effect is possible without randomised control groups. Synthetic controls and interrupted time series offer practicable alternatives to randomised controlled designs, which at community level can be carried out only with great effort. That matters in Europe, where a shortage of studies in the setting reviewers care about, rather than doubt about the model, is what has kept the most recent independent verdict on CTC cautious (see the evidence page).

The importance of the mobilisation phase

The early effect in neighbourhood B shows the relevance of intensive preparation. A European CTC community should:

• plan at least six to twelve months for mobilisation;
• secure broad participation before programmes start;
• understand the mobilisation itself as an intervention.

Adapting to local conditions

The differing results show that CTC has to be adapted to local conditions. Recommendations:

• in large cities, focus on manageable districts and neighbourhoods rather than the whole city;
• provide more resources for coordination in larger areas;
• use flexible implementation models according to context.

Conclusion: what the Denver study means for European prevention

The evaluation by Kingston et al. (2026) provides empirical evidence for the effectiveness of CTC in preventing youth violence, confined to one of the two neighbourhoods studied. The 75 % reduction in violence rates in neighbourhood B over five years is an encouraging result that underlines the importance of systematic, community-based prevention; the absence of an effect in neighbourhood A shows at the same time that implementation conditions decide success. One well-designed quasi-experimental study in one neighbourhood does not settle the wider question of CTC’s effect on violence, but it adds a data point in the same direction as the randomised evidence, from an independent research group and from a setting of real disadvantage.

For European communities, several findings follow:

1. Science-based approaches are practicable and effective – when they are adapted to the local context.
2. Mobilisation is central – the process matters as much as the programmes.
3. The size of the area matters – implementation strategies must fit it.
4. Sustainability is possible – but it requires continuous support.