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Introduction
In the two decades since Sherman (1998) described a framework for evidence-based policing (EBP) it has become the focus of a growing and increasingly global movement. Among other developments there has been a very significant growth in experimental research on policing (Neyroud, 2017), the establishment of the Campbell Collaboration Crime and Justice Group, the creation of âWhat Worksâ centers, the development of the Society of Evidence-based Policing, and the Division of Policing within the American Society of Criminology.
Four years before Sherman published his paper, Bayley (1994) had cast doubt on the ability of the police to affect crime. A growing number of experiments, many now supporting systematic reviews, have since shown that police can be effective by adopting targeted approaches, such as hot spot policing, strategies including problem-oriented and community policing, and multi-agency interventions such as focused deterrence (Weisburd and Majmundar, 2018).
Despite this, EBP has been accused of being too focused on crime and disorder outputs, too reliant on US research, and too dependent on randomized controlled trials at the expense of a wider range of research methods (Fielding et al., 2020). The last point has been consistently overplayed by EBPâs critics. In Shermanâs original definition of EBP, it was described as the âbest available research on the outcomes of police work to implement guidelines and evaluate agencies, units, and officersâ (1998: 3). Over the 20 years since, EBP has developed, as set out in Shermanâs (2013) âTriple Tâ model, into a whole institutional framework and not one confined to the evaluation of operational strategies and interventions, nor exclusively to the advocacy of experimental methods.
The extent to which EBP is overdependent on US policing research and, thus, a largely Anglo-Saxon phenomenon, raises the wider question as to the extent to which EBP has developed into an applied science of police leadership and management, capable of supporting a global movement for reform of policing. To that end, this chapter will explore three very different case studies in which EBP has been an important framework. The case studies will be used to examine the achievement, challenges, and obstacles to EBPâs dissemination and development as a global strategy for policing and policing reform.
Diffusion, dissemination, reform, and transformation
One of the most important contributions to the study of innovation and its dissemination has been Rogersâ (2003) diffusion of innovation theory. Rogers synthesized a range of different disciplines into a theory which focused on the social system for diffusion. Three dimensions of that system were particularly important: the characteristics of the innovation, the adopters, and the organization. Within this eco-system Rogers theorized a process of adoption starting with the acquisition of knowledge and working through persuasion and initial decisions to implementation and ultimately confirmation or embedded adoption. Rogers also identified five characteristics which he considered to have a relationship with the speed and extent of adoption: (1) relative advantageâthe extent to which the innovation is an improvement; (2) compatibility with the values, experience, and needs of potential adopters; (3) complexityâthe difficulty in understanding and using within the organization; (4) triability or the extent it can be tested before commitment; and (5) observabilityâthe extent to which the innovation provides tangible results. In the case studies that follow, the analysis will draw on Rogersâ theory and proposed questions to assess the evidence-based innovation.
The chapter will also rely on a process of reflection because the author has been personally involved in each case study as both police professional and academic. In the first, during a 30-year police career, the author led on the development of the national policy and legislation for police-led diversion and then, as a researcher, was the principal investigator for the Turning Point experiment in Birmingham. In the second, as Chief Constable of Thames Valley and CEO of the National Policing Improvement Agency, the author was responsible with colleagues for initial testing (Tuffin et al., 2006) and subsequently led the national rollout of neighborhood policing and, then, more recently conducted an evidence review and developed an implementation checklist for the United Nations Office of Drugs and Crime (UNODC). In the final example, the development of EBP in India, the author has had more than 30 years of involvement with Indian policing, ranging from a study exchange in 1991, to directing the Cambridge program for senior Indian police officers and, most recently, to presenting EBP to the Prime Minister and the India Director-General of Police conference. In Rogersâ terms, the author has been engaged in each element of shaping knowledge, persuasion, making decisions, implementation, and adoption.
All three case studies are also concerned with reform of the police. In the Indian case study, there was an additional, personal dimension in that one of the members of the Cambridge program team, over a period of ten years, was Professor David Bayley. Bayleyâs work on comparative policing research and police reform was ground-breaking and based on a lifetime of field research and engagement with senior police officers. He developed a model of police reform which he set out in Changing the Guard (2006). Bayley argued that all effective police reform needed to start with close attention to the legal framework and independent oversight. This was then supported by four themes that have a strong relationship with evidence-based policing: recruiting and retaining the right sort of people; developing the capacity of police executives to manage reform; making the prevention of crime as it affects individuals the primary focus of policing; and requiring legality and fairness. He went on to add that police reform was rarely, if ever, achieved by focusing on reorganizing, equipping, or training the police.
In our paper on âPolice Scienceâ (Weisburd & Neyroud, 2011), we also debated the potential contribution of evidence to transforming the police. For this to happen, we argued that the police need to accept ownership of the science of policing, driving it, adopting it, and implementing it across the organization. Like Bayley, we agreed that transforming the police requires more than rules, regulation, and oversight. It requires a science-based transformation of the work of the police and the police organization. For us, for Bayley, and for Sherman, real reform of policing requires the use of the best science and best evidence to support the continual improvement and development of what the police do, how they do it as well as how they are held to account for it, and the legal frameworks within which they operate.
Case study 1: The testing and dissemination of police-led diversion models
Police-led diversion has been implemented in many international jurisdictions. Most models aim to divert offendersâmost frequently young offendersâfrom the formal criminal justice system, with either a caution or warning or a more structured set of required conditions. The emergence of serious interest and investment in police-led diversion can be traced to the 1960s. In the USA, it was the recommendations of the Presidentâs Commission on Law Enforcement and the Administration of Justice in 1967 that gave real impetus (Klein, 1976). In the UK, by 1976, most police forces had juvenile cautioning schemes (Ditchfield, 1976). During this period, a range of diversion programs for juveniles was being developed and used on both sides of the Atlantic, as well as in Australia and New Zealand.
In the UK, police-led diversion has been universally implemented across all agencies (even if with some variations). In the USA, where only a third of agencies had schemes, there were three types: diversion of juveniles; mental health diversion often linked to crisis intervention teams; and schemes targeting low-level adult offenders (Tallon et al., 2018). In both the UK and the USA there was a strong correlation between police-led diversion schemes and a strong ethos of community policing.
As to whether these schemes were âevidence-based,â Tallon et al. (2018) and Bird et al. (2018) documented an increase in the published research, notably on mental health diversion schemes. However, in terms of âtriability,â many of the early experiments were testing bespoke interventions evaluated by the design team, tended to have small samples, and were routinely short on detail of the implementation issues encountered (Neyroud, 2017).
In the UK, since 2010, there has been a renewed interest in testing different approaches to police-led diversion with five major experimental studies: Turning Point (2011â2014) tested a deferred prosecution with conditions (Neyroud et al., 2016) and has been replicated in North London; Operation CARA explored a group treatment for low-harm domestic violence offenders as part of a conditional caution (Strang et al., 2017); Operation Checkpoint (2015â2020) included an offender triage approach linked to deferred prosecution with conditions (Urwin, 2016); and the Ministry of Justice piloted a two-tier model with a three police force quasi-experiment (Ames et al., 2017).
Another important aspect of the shift from the earlier studies to a more evidence-based approach has been the investment in systematic reviews. There have been two Campbell Collaboration reviews, the first exploring the âformal system processing of juveniles.â Petrosino et al. (2010) found that âjuvenile system processing [through court prosecution] appears to not have a crime control effect, and across all measures appears to increase delinquencyâ (p. 6). The second Campbell review examined the effectiveness of police-led diversion for young offenders. It found a modest but significant benefit in reduced reoffending (Wilson et al., 2018).
Neither systematic review was able to provide a clear answer as to whether diversion with conditions or without was likely to be more effective. The extent to which the scheme was effectively implemented and how well the process of setting conditions was managed were critical variables affecting success. Both reviews found only North American- and Australian-based eligible studies and were exclusively ...
