Published: October 9, 2020

Mazerolle, L., Eggins, E., Cherney, A., Hine, L., Higginson, A., & Belton. E (2020). Police programmes that seek to increase community connectedness for reducing violent extremism behaviour, attitudes and beliefs. Campbell Systematic Reviews, 16(3).


Lorraine Mazerolle, Elizabeth Eggins, Adrian Cherney, Lorelei Hine, Angela Higginson, and Emma Belton.



Police can play a role in tackling violent extremism through disrupting terrorist plots and by working with communities to identify individuals at risk of radicalisation. Police programmes to tackle violent extremism can involve a range of approaches and partnerships. One approach includes efforts to improve community connectedness by working to address social isolation, belonging, economic opportunities and norms and values that may lead people to endorse or support violent extremist causes and groups. The assumption is that the risk of an individual being radicalised in the community can be reduced when police work in pothe international legal ordersitive ways with community members and groups to mobilise and support activities that help generate a sense of belonging and trust. Police programmes that build a sense of belonging and trust may help ensure individuals are not influenced by activities that violent extremists use to attract support for their cause.


The review aimed to systematically examine whether or not police programmes that seek to promote community connectedness are effective in reducing violent extremist behaviours, attitudes and beliefs. The review also sought to identify whether effectiveness varied by the intervention type and location.

Search Methods

Using terrorism‐related terms, we searched the Global Policing Database to identify eligible published and unpublished evaluations between January 2002 and December 2018. We supplemented this with comprehensive searches of relevant terrorism and counter‐terrorism websites and research repositories, reference harvesting of eligible and topic‐relevant studies, forward citation searches of eligible studies, hand‐searches of leading journals and consultations with experts.

Selection Criteria

Eligible studies needed to include an initiative that involved the police, either through police initiation, development, leadership or where the police were receivers of the programme (such as a training programme) or where the police delivered or implemented the intervention. The initiative also needed to be some kind of a strategy, technique, approach, activity, campaign, training, programme, directive or funding/organisational change that involved police in some way to promote community connectedness. Community connectedness was defined as being community consultation, partnership or collaboration with citizens and/or organisational entities. Eligible outcomes included violent extremism, along with radicalisation and disengagement which are considered to be attitudinal and belief‐based components of violent extremism. These outcomes could be measured via self‐report instruments, interviews, observations and/or official data. To be included, studies could utilise individuals, micro‐ or macroplaces as the participants. Finally, studies needed to provide a quantitative impact evaluation that utilised a randomised or quasi‐experimental design with a comparison group that either did not receive the intervention, or that received “business‐as‐usual” policing, no intervention or an alternative intervention.

Data Collection and Analysis

The systematic search identified 2,273 records (after duplicate removal). After systematic screening across two stages (title/abstract and full‐text), just one study (reported in two documents) met the review eligibility criteria. Standardised mean differences (SMD) were used to estimate intervention effects for this single study and risk of bias was assessed using the Cochrane Risk of Bias in Non‐Randomised Studies‐Interventions tool (ROBINS‐I).


The single eligible study (n = 191) was a quasi‐experimental evaluation of the Muslim‐led intervention—World Organisation for Resource Development Education (WORDE)—conducted in the United States in 2015. The intervention comprised three components: community education, enhancing agency networks and multicultural volunteerism activities. Self‐report data were collected from youth and adults who were civically engaged, sensitised to issues of violent extremism and who had existing cooperative relationships with law enforcement and social services. The comparison group comprised matched participants who had not engaged with the WORDE programme. The outcomes most closely aligned with conceptual definitions of deradicalization, specifically levels of acceptance and/or engagement with cultural and religious differences or pluralistic views and modification of group or personal identity. Based on single survey items, the SMD ranged from small to medium in favour of the treatment group aside from one item which favoured the comparison group (“I make friends with people from other races”, SMD = −0.51, 95% CI: −0.82, −0.19). However, of the nine SMDs calculated, six had confidence intervals including zero. These effects should be interpreted with caution due to the study’s overall serious risk of bias. It is important to note that it is not explicitly clear whether the evaluation participants in the treatment group were all directly exposed to the two intervention components that involved police. Hence, these evaluation outcomes may not be direct measures of how effect police were at countering violent extremism by promoting community connectiveness.


The aim of this systematic review was to examine whether or not police programmes that seek to promote community connectedness are effective in reducing violent extremist behaviours, attitudes and beliefs. There is insufficient evidence available to ascertain whether such interventions achieve these outcomes. This finding is the result of the fact that interventions that have been evaluated tend to be characterised by evaluation designs that do not adopt experimental or quasi‐experimental approaches or use outcomes that are outside of scope for this review. While the volume of studies identified provide support for the assertion that police can play a role in tackling violent extremism by participating in, and implementing, programmes that promote community connectedness, it is unclear at this time if such approaches work in reducing violent extremism. Whilst we conclude that investment needs to be made in more robust methods of evaluation to test for programme effectiveness, we acknowledge that conducting evaluation and research in the area of counter‐terrorism/violent extremism is challenging.