Young people, ‘knife’ and ‘gun crime’: policy in an evidence vacuum?

Arianna Silvestri examines the evidence available to support interventions in this high-profile area.

A comprehensive review of the most rigorous international evidence over the last decade has revealed a dearth of successful initiatives to reduce violence in the long term.

The research, carried out by Centre for Crime and Justice Studies on behalf of 11 MILLION, shows that remarkably few interventions on youth knife and gun crime, nationally and internationally, have been subjected to rigorous research or independent assessment. This is despite the fact that many programmes are taking place in the UK which aim to affect young people's carrying or using of weapons.

Looking for reliable evidence

Our review examined thousands of studies of interventions in the area of young people and weapons, and selected the most rigorous ones according to established standards (the Maryland Scientific Methods Scale – SMS – was applied to quantitative research and the Global Assessment of Evaluation Quality to qualitative studies). We considered only research fitting the higher parameters in both assessment models (in SMS, studies using at least a comparison group which matches in characteristics the group to which the intervention is applied). We prioritised meta-analyses and systematic reviews and assessed unpublished as well as published work.

Very few studies overall met the highest standards of research (in SMS, randomised controlled trials). In this country, evaluations may be premature in the case of recent projects, although we also found cases where external evaluations had not been given any budgetary priority – hence they did not take place. In other cases assessments could not be properly carried out because of a variety of projects ‘malfunctions’, e.g. the unavailability of data or ‘mission drift’.

What we found: young people and guns

Most research about the carrying and use of firearms comes from the United States, which is unsurprising in view of the scale of gun availability and youth gun violence in that country. What was surprising, however, was to find that most strategies had not been subject to rigorous evaluations. Of the few that had, none produced evidence of significant long term reductions in youth gun violence.
There is more clarity in US literature on what does not appear to work in reducing gun violence among young people:

  • purely suppressive approaches (like untargeted crackdowns, street sweeps);
  • attempts to disrupt illegal supply of firearms, bans and restrictions on buying and licensing;
  • buy-back/exchange programmes;
  • guns searches and seizures;
  • mandatory minimum sentences for gun-related offences.

Some intensive strategies, targeted at particular places (‘hot spots’) and/or groups (like serious or prolific offenders), have shown a positive effect in reducing youth homicides and other violence – but only in the short term, with the problems resurfacing as soon as the interventions are over. There is also a possibility of crime being displaced to other locations or different times, and of local communities feeling alienated by intensive enforcement. These strategies, referred to as ‘community safety initiatives’ follow the model first developed in Boston's Operation Ceasefire (Braga and Winship, 2009), which has been highly influential. Community safety initiatives have helped demonstrate that approaches which are locally based, combine both prevention and suppression methods and which are carried out by agencies working in coooperation (and ‘pulling’ every ‘lever’) are more effective than single-focus interventions by agencies working in isolation.

Although many UK approaches appear to follow ‘hot spot’ techniques, it is doubtful whether any have replicated the breath and depth of Boston's resource-intensive ‘pulling levers’ operation, with its concerted effort by government and civic bodies at all levels to reach the most at-risk youth by a variety of hands-on approaches, combining policing with intensive social support. It is also of course debatable whether strategies originating in specific cultural and legal contexts can be transferable to different countries and situations.

A problem of weapons, or a problem of violence?

Outside the UK, there appears to be very little specific interest in weapons among researchers and policy makers (with the exception, as we have seen, of guns in the US). Interest is concentrated on youth violence more generally and on preventing it from happening in the first place, rather than intervening (usually via the criminal justice system) once it has occurred.

Although having a knife or gun increases the risk and seriousness of injury, focusing upon the weapons themselves can arguably be a distraction from the wider context of and reasons for violence among young people. Moreover, injury – and death – can be inflicted by a variety of other means (e.g. a broken bottle, a baseball bat, punches or kicks). Policies which concentrate on knives or guns run the risk of missing the wider stimulants and conditions (e.g. poverty or relative deprivation, abuse, poor education, unemployment, substance abuse, racism, cultural glorifications of violence) which play a complex part in engendering or facilitating violence.

A matter of public health

A public health approach underpins the most promising prevention strategies, which focus on intervening early to minimise harmful circumstances in young people's lives. Interventions like nurse visitation programmes, early parent training and therapeutic foster care have shown long-term positive effects on youth conviction rates. School-based programmes focusing on cognitive skills have also proven to have a statistically significant impact on aggressive and disruptive behaviour, as have conflict resolution programmes in reducing recidivism by violent young offenders.

On the other hand, research clearly shows that ‘zero tolerance’ and deterrent approaches (e.g. prison tours, or ‘Scared Straight’ as they are known in the US) not only do not work in reducing violence, but are actually counter-productive.

Surveys and the 'voice' of young people

Invariably, polls carried out in England show that young people feel they need to carry weapons in order to protect themselves, in areas they perceive to be unsafe. However, opinion polls on sensitive topics are methodologically weak: they offer views at one point in time, without revealing the variety of factors which may have influenced such views; they are prone to selection bias (when only certain types of people responding), which has an impact on claims to representativeness of the sample, and to response errors (when respondents misunderstand a question or intentionally give an untrue answer).

A better way to gain an insight into young people's perceptions, choices and values is through in-depth qualitative research. Our report explores the best examples, providing a nuanced, layered perspective which sheds some light on young people's motivations, as well as the symbolic meanings they attach to implements like guns or knives. Some have weapons to help maintain their reputation and the respect of others; but weapons are also used while carrying out economically-motivated activities (e.g. illegal drugs or acquisitive crimes), in the context of limited access to legitimate means of achieving status and social mobility.

Asking questions

For us, this piece of research also raised a number of unresolved issues. Below are some of them.

What are these entities referred to as ‘knife crime’ and ‘gun crime’ anyway? What is it really meant by them? How much ‘knife crime’ or ‘gun crime’ is out there?

To what extent is the fear, which appears to spur some young people to carrying weapons, exacerbated by media reporting? Is the media focus distorting the type and scale of the problem?
In spite of the attention and hyper policy activity surrounding young people with guns and knives, very little effort appears to have gone in into finding out ‘what works’. Why?

Do we need to tailor interventions specifically to the issue of guns and knives? There is no clear evidence to confirm this, and doing so may distract attention from potentially more effective policy responses which tackle underlying causes. Research shows that violent crime, including weaponised crime, is carried out (and experienced as victims) by a minority of young people, living in areas and conditions of social disadvantage (where, for a variety of reasons, their chances of personal achievement are curtailed). Tackling cycles of deprivation and exclusion would seem a policy imperative. 

The CCJS report on young people, knife and gun crime, produced for 11 MILLION, is available at:


Braga, A. and Winship, C. 2009, ‘What can cities do to prevent serious youth violence?’, Criminal Justice Matters, 75, pp. 35 – 37.