The evidence for criminal justice interventions for preventing radicalisation, extremism and terrorism is unevenly distributed across criminal justice agencies, outcomes and geographies
There is a relatively limited body of evidence related to criminal justice interventions for preventing radicalisation, violent extremism and terrorism. Most of the evidence is focused on policing interventions and is situated in high-income countries such as the USA.
What is this evidence and gap map (EGM) about?
Criminal justice agencies (police, courts and corrections) are well positioned to help prevent the radicalisation of individuals and groups, to stop those radicalised from engaging in violence, and to reduce the likelihood of terrorist attacks.
Decisionmakers need to know what the available evidence is and what remains unstudied. This EGM shows the existing evidence and gaps in the evaluation research, allowing stakeholders to identify future funding priorities for research and programme development.
The interactive EGM is available here: https://onlinelibrary.wiley.com/pb-assets/assets/18911803/EGM%200059%20Sydes%20Map_Expanded_Standard-1695731881.html.
What is the aim of this EGM?
The aim of this EGM is to show all the available evidence from systematic reviews and high-quality impact evaluations of criminal justice interventions that seek to prevent radicalisation, violent extremism and terrorism.
What studies are included?
The EGM includes impact evaluations and systematic reviews assessing the effect of criminal justice interventions on preventing radicalisation, violent extremism and/or terrorism.
Included studies had to report an estimate of the quantitative impact of an intervention. The studies were broadly categorised as to whether the intervention involved police, courts, corrections (custodial and community-based) and if they were multi-agency, involving at least one criminal justice partner.
No limits were placed on outcomes. Outcomes were broadly categorised under nine thematic groups: terrorism; extremism/radicalisation; non-terror related crime and recidivism; citizen perceptions/intentions towards the criminal justice system and government; psychosocial factors; criminal justice practitioner beliefs, attitudes and/or behaviour; racially targeted criminal justice practices; investigation efficacy and organisational factors.
The map includes 70 studies from 71 documents: two systematic reviews and 68 impact evaluations. The included impact evaluations are predominantly quasi-experimental studies.
What are the main findings of this map?
The studies are unevenly distributed across criminal justice agencies. Policing is the most heavily populated area of the map, representing 58 of the 70 studies. There are relatively few studies that evaluate courts and prison interventions for preventing terrorism/radicalisation. No studies evaluate the impact of community corrections interventions.
The most common outcome measures are related to terrorism (n=20), including terrorism incidents (n=14), fatalities caused by terrorism (n=4), citizen willingness to report terrorism (n=2) and diffusion/displacement effects (n=1).
Investigation efficacy (for example detection of guilt, detection of suspicious activities, and information sharing) and organisational factors (such as inter-agency collaboration and uptake of Homeland Security initiatives) are also frequently evaluated. However, very few studies evaluate intervention impact using measures of radicalisation/extremism.
The majority of studies included on the EGM are situated in the USA or other high-income countries.
What do the findings of the map mean?
This EGM aims to provide a comprehensive and systematic display of the existing evidence on criminal justice interventions which aim to prevent radicalisation, violent extremism and/or radicalisation. By locating and visually presenting all available evidence, the EGM improves access to high-quality impact evaluations.
We suggest future counter-terrorism research pay attention to building researcher-practitioner partnerships that focus on scientific quality, with a clear agenda to build a more robust evidence base.
How up-to-date is this EGM?
The search was carried out between June and August 2022. The authors searched for studies published up to December 2021.
The Campbell Collaboration is an international, voluntary, non-profit research network that publishes systematic reviews. We summarise and evaluate the quality of evidence about programmes in the social and behavioural sciences. Our aim is to help people make better choices and better policy decisions.