What Works to Reduce Crime?: A Summary of the Evidence

EXECUTIVE SUMMARY

RESEARCH AIMS AND OVERVIEW

This evidence review was undertaken to support strategic thinking on what works to reduce crime in relation to the following three key strategies:

1. Targeting the underlying causes of crime so that the urge or need to offend is reduced;
2. Deterring potential offenders by ensuring that the cost of offending is greater than the benefits.
3. Increasing the difficulty of offending by reducing opportunities to commit crime.

The aim of the review was to examine the research evidence on reducing crime in relation to both the underlying causes of crime (that may originate in the early life course) and the immediate antecedents of a criminal event. This is in recognition of the need to address both factors in order to reduce crime effectively and to highlight key messages for the Building Safer Communities programme. More broadly, it aimed to identify whether the Scottish Government should consider additional or alternative measures to tackling crime. It did not consider strategies to reduce the risk of recidivism (or re-offending) however, as this is the focus of a separate published review of the literature on Reducing Reoffending^[1]. Figure 1 provides a summary of the four key strategies for reducing crime in diagrammatic form.

It is important to note that the review does not purport to provide a comprehensive and definitive account of the evidence on what works to reduce crime, but rather constitutes a collation of the material which could be identified and accessed within a relatively short space of time. It is hoped that the work will provide a foundation upon which new and existing research evidence may be added as it becomes available or is identified in the future.

PART ONE: ADDRESSING THE UNDERLYING CAUSES OF CRIME

A considerable body of research posits that offending is the result of a natural predisposition which has its roots in biology (associated with genetic, hormonal or neurological factors). However, research has also shown that the impact of biological factors becomes less salient once environmental and social factors are taken into account. These societal/environmental factors which shape behaviour are the mainstay of the paper's focus.

The review highlighted the importance of parenting as being a crucial factor in the development of self-control. Lack of self-control is associated with a higher propensity towards offending behaviour and a range of other negative life outcomes (in terms of education, employment and relationships). Continued investment in early-years parenting programmes is therefore crucial in the promotion of self-control as well as in improving life changes more generally. Evidence also suggests that offending behaviour is linked to the experience of abuse and neglect, which underlines the importance of a child protection system which identifies and addresses this as early as possible.

While tackling parental/family issues is highlighted as crucial, it is only one part of the answer, with research which suggests that the wider social context within which the family resides is also important. Indeed, evidence from the Edinburgh study of Youth transitions and crime found that living in disorganised and deprived neighbourhoods could lessen the impact of good parenting^[2].

The importance of the school environment is highlighted as crucial in addressing the causes of offending and in ensuring a range of positive outcomes for young people. It is also important in providing a diversionary role from offending activity (and reducing available time to engage in criminal activity). Indeed evidence from Samson and Laub and the Edinburgh Study of Youth Transitions and Crime suggests that attachment to school is a key protective factor and that school exclusion may lead to a negative pattern of offending.

There are examples of school-based interventions that have been effective in reducing the risk of offending. A review of these found that the most effective strategies in encouraging positive behaviour involved the clear enforcement of boundaries around acceptable and unacceptable behaviours. These entailed adherence to an agreed framework for managing discipline by clearly setting out, clarifying and reinforcing school rules and expectations (e.g. through the use of campaigns, ceremonies or similar techniques). In addition, cognitive-behavioural approaches have been highlighted as being effective in reducing crime. Of wider policy interest perhaps is the use of nurture groups to promote positive behaviours, evidence from which suggests a range of positive outcomes in terms of the social, emotional, behavioural and educational functioning of children.

Although early life experiences are highlighted as important in shaping an individual's life chances and their likelihood of becoming involved in offending, there is recognition that key factors in adulthood may affect outcomes. Strong societal attachments in the form of stable employment and good familial relationships (especially marital) are identified as key factors in promoting law abidance. Despite the importance of employment being highlighted, there is a dearth of robust evidence on the impact that employment interventions may have in reducing re-offending. However, research does suggest that offenders and those who are at risk of offending may require assistance with other issues such as education or motivation in order to help them move towards employment and that programmes should provide appropriate support. One key policy implication is that criminal justice sanctions should (wherever possible) minimize the impact on employment prospects and familial relations.

There is a strong body of research which links offending to drug and alcohol misuse and tackling this is already a key Scottish Government priority. However, the causes of misuse may be rooted within low levels of self-control. It is therefore argued that measures to improve levels of self-control via more consistent and effective parenting interventions could help reduce offending. Figure 2 on page 9 provides a summary diagram of the key issues in relation to addressing the underlying causes of crime.

PART TWO: DETERRING OFFENDING BY ENSURING THE COSTS OUTWEIGH THE BENEFITS

This section explored the effectiveness of sanctions imposed by the criminal justice system on deterring potential offenders as well as methods of informal social control. More informal social control refers to the generation and reinforcement of strong cultural norms that encourage compliance. In addition, it reviewed the existing evidence looking at the relationship between the severity, certainty and celerity (swiftness) of formal criminal justice sanctions and their impact on crime rates.

In relation to increased certainty of punishment, research suggests that this is effective in reducing crime. However, there is less robust evidence in terms of the relationship between the severity of punishment and crime rates, and limited available evidence on the celerity of punishment. Evidence suggests that increasing police numbers may be effective in reducing crime, particularly in relation to property-related crime. However further evidence is required to establish a causal link between the two. The effectiveness of increased police numbers is also dependent on how they are deployed and targeted, with evidence to suggest that increasing patrols in crime hotspots has been shown to be associated with a reduction in crime. A community policing approach is also associated with a decrease in crime but it is difficult to establish exactly which aspects of this make it effective (due to the many different elements involved). Overall, substantial evidence indicates that the way in which police officers are deployed has the greatest impact on preventing serious crime, for example through directed patrols, proactive arrests and problem solving at high crime hot spots.

Also important is the degree to which the criminal justice system and its institutions are perceived as legitimate. This was strongly correlated with compliance with the law (even when personal morality was controlled for). It is also linked with greater confidence and satisfaction with the justice system and greater co-operation in interactions with it. Building and maintaining public trust in the criminal justice system and its agencies is therefore considered crucial.

Restorative justice approaches which attempt to deter potential offenders by highlighting the social costs of crime and the impact upon the victim and wider society provides potential, with some evidence to suggest that this approach is effective. However, there is a lack of robust research on this topic.

In terms of the link between signs of disorder and crime as per the 'broken windows' thesis, collective efficacy (or the extent to which a community is cohesive and able to work together to achieve goals), it is argued is a more important underlying factor. Indeed, the degree of collective efficacy within a community was identified as a more powerful predictor of violence, burglary and robbery than were signs of social and physical disorder. Research suggests that some communities are able to deploy an informal guardianship role, but there is a lack of clarity as to whether social policy has a role in this. It is suggested that the Glasgow Community Health and Wellbeing Research and Learning Programme (GoWell), in which investment has been made in the physical infra-structure of communities, may allow exploration of the impact of regeneration on crime rates. An assets-based approach to collective efficacy may render positive results, by involving communities themselves in the design and implementation of initiatives to reduce crime. However, there is currently a lack of evidence in terms of the effectiveness of this approach. Furthermore, it should be recognised that concentrated disadvantage was the factor most strongly associated with disorder and crime. Figure 3 on page 10 provides a summary diagram of the key issues in relation to deterrence and ensuring that the costs of offending outweigh the benefits.

PART THREE: REDUCING THE OPPORTUNITIES FOR OFFENDING

The third section explored situational crime prevention activities which are sometimes considered as 'fall-back' or 'last-resort' strategies for reducing crime for those for whom the first two strategies are ineffective. This refers to measures which are intended to make it more difficult for people to offend. Central to this is the modification of the physical environment to ensure that opportunities for crime are reduced. Also considered are strategies which include restricting the movement and activities of those who are at risk of offending as well as imposing societal restrictions (i.e. stricter controls re access to weapons), as well as diversionary activities with potential offenders at peak risk of offending. Figure 4 provides a summary of the key issues related to reducing the opportunities for re-offending.

Situational crime prevention approaches are effective in reducing crime. Evidence suggests that environmental changes including improving street lighting, introducing exact fare requirements on public transport and avoiding overcrowding in public venues can be effective both in reducing acquisitive crime and violent crime. It is also suggested that interventions accompanied by widespread publicity are even more effective by deterring potential offenders (even before the introduction of the initiative).

Research finds that situational crime prevention activities which improve the local environment may lead to an increase in community and civic pride and therefore improve collective efficacy. Although also highlighted within the literature is the potential for harm via the erection of physical barriers that segment communities, rather than helping to bring them together.

There has been increasing emphasis in recent years on the potential for removing opportunities for crime via the design of the built environment. Urban planning initiatives such as 'Secure by Design' (which promotes good practice in planning to ensure that crime prevention is taken into account right from the outset) have been shown to be effective in reducing crime. This is achieved via adherence to a number of key principles at the planning stage aimed to reduce crime, disorder and fear of crime, including the maximisation of natural surveillance, informal social control and minimum numbers of access points and standards of physical security. Sharing good practice and awareness raising regarding measures to improve the built environment and reduce crime could further increase the effectiveness of this approach.

Additional approaches include the restriction of access to weapons, drugs and alcohol. In terms of weapons, evidence on the restriction of access to knives (the most commonly used weapon in Scotland) suggests that broad strategies to restrict access to knives through the application of a range of approaches are associated with a reduction in knife injuries. A strong body of evidence suggests that restrictions on the availability of alcohol, including minimum pricing, ensuring a minimum age of purchase is adhered to, reducing the number and density of premises where alcohol is sold and restricting days and hours of sale, are all associated with a reduction in crime.

In terms of the impact of diversionary recreational activities, while there was no evidence to suggest that there is a causal relationship between participation and a reduction in crime, many large scale diversionary projects have demonstrated some success in reducing offending. Indeed, the difficulty is in disentangling the impact that other social processes and interventions may also have had on crime rates. However, diversionary activities are beneficial in helping engage young people in positive activities which may lead to the provision of greater social support, positive role models and other protective factors. Overall though, the importance of tackling the underlying problems which drive young people towards offending behaviour is highlighted as a key priority in the effort to reduce crime.

Figure 1: What works to reduce crime? Key messages from the four strategies

The stimulus for this review was the development of a logic model, which set out four key strategies for reducing crime, summarised above.

*The review did not consider strategies to reduce the risk of recidivism however, as this is the focus of a separate published review of the literature on reducing re-offending.

Figure 2: Addressing the underlying causes of crime - summary

Figure 3: Deterrence - ensuring the costs of offending outweigh the benefits - summary

Figure 4: Reducing the opportunities for offending - summary