The Campbell Collaboration is a nonprofit organization that promotes evidence-based policymaking through the production of systematic reviews, summaries and syntheses of policy-relevant evidence. Each post in this series includes excerpts from the Campbell Collaboration’s “Plain Language Summaries” in the subject areas of crime & justice, education, and social welfare.

Body-worn cameras’ effects on police officers and citizen behavior Authors: Cynthia Lum, Christopher S. Koper, David B. Wilson, Megan Stoltz, Michael Goodier, Elizabeth Eggins, Angela Higginson, Lorraine Mazerolle. Published September 9, 2022. Subject Area: Crime & Justice  

This Campbell systematic review summarizes the evidence from 30 studies of the effects of body-worn cameras (BWCs) on several officer and citizen behaviors. The majority of studies are from the USA.

Overall, the way BWCs are currently being used may not substantially affect most officer or citizen behaviors. The use of BWCs does not have consistent or significant effects on officers’ use of force, arrest activities, proactive or self-initiated activities, or other measured behaviors. Nor do BWCs have clear effects on citizens’ calls to police or assaults or resistance against officers. Analysis suggests restricting officer discretion in turning on and off BWCs may reduce police use of force, but more assessment is needed.

Full Report: https://www.campbellcollaboration.org/better-evidence/impacts-of-body-worn-cameras-in-policing.html

Accommodation-based interventions for individuals experiencing, or at risk of experiencing, homelessness  

This Campbell systematic review of qualitative and quantitative evidence examines how useful accommodation-based [i.e., housing-based] approaches are for people experiencing homelessness… Twenty five out of the 28 studies are from the USA, two from Canada and one from the UK. The quality of the research is generally low and represents important weaknesses in the evidence base.

Interventions which provide the highest levels of support and do not place rules on the person receiving the intervention are best at improving housing stability and health outcomes. Interventions which offer the lowest levels of support and do not place rules on the person might harm those individuals. For those individuals, housing stability and health outcomes were worse than for all other interventions, including individuals who are not receiving any intervention at all.

Full Report: https://www.campbellcollaboration.org/better-evidence/homelessness-accommodation-based-interventions-network-meta-analysis.html

‘No Excuses’ charter schools for increasing math and literacy achievement in primary and secondary education Authors: Sarah Krowka, Alexandria Hadd, Robert Marx. Published: August 28, 2017. Subject Area: Education

The ‘No Excuses’ charter school model focuses heavily on high academic expectations, rigid and consistent discipline, extended instructional time, intensive teacher training, and increased parental involvement.

This Campbell systematic review examines the effects of No Excuses charter schools on students’ math and literacy achievement gains compared to similar students in public schools. The review summarizes evidence from 18 studies [conducted in the United States spanning from 1990-2015], including 5 randomized controlled trials and 13 quasi-experimental studies.

No Excuses charter schools, on average, produced larger math and literacy achievement gains for their students than their public school peers—with higher gains for math. These benefits increase for three years, at which point the achievement gains stabilized or returned to lower gains. 

Full Report: https://www.campbellcollaboration.org/better-evidence/charter-schools-maths-and-literacy-primary-and-secondary-education.html