Body Warn Cameras (BWC) are a commonly used frontline risk control for occupational violence and aggression risks. On the surface, it makes sense – if a person is being filmed, then they’re less likely to be violent. But is that true? Research doesn’t support that conclusion. In fact, several studies suggest that the wearing of BWCs may increase the risk of workplace violence.
Here are some studies that look across different occupations and sectors, with some surprising commonalities in their findings.
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Wilson et al. (2023) – Exploring the use of body-worn cameras in acute mental health wards
Introduction
Body-worn cameras (BWCs) are increasingly used in mental health wards as a violence prevention tool, but research on their effectiveness, especially from the patient perspective, is limited.
Aim
To explore the perspectives of patients, staff, and management on BWCs and their potential impact on violence and aggression in inpatient mental health settings.
Research Question
How do patients, staff, and management perceive BWCs in acute mental health wards, and what are the anticipated impacts on violence and aggression?
Methodology
- Exploratory qualitative study
- Semi-structured interviews with 24 patients, 25 staff, 6 nursing directors, and 9 community-based patients across five hospitals in England
- Reflexive thematic analysis
Results
- Both staff and patients cited a culture of mistrust and feeling unsafe.
- BWCs may intensify power dynamics and undermine therapeutic relationships.
- No indication that BWCs would deter violence/aggression.
- BWCs may be useful for safeguarding and staff training, but ethical concerns remain.
Discussion
There is a lack of evidence supporting BWCs as a deterrent for violence in mental health settings. BWCs may have unintended negative consequences, such as undermining trust and therapeutic relationships.
Gaps
- Lack of empirical evidence on the deterrent effect of BWCs in mental health wards.
- Ethical concerns and patient perspectives are underexplored.
Conclusion
No support among staff or patients for the idea that BWCs deter violence/aggression. BWCs may have a role in safeguarding and training, but not as a primary violence prevention tool.
Practical Implications
- Prioritise systemic interventions and address underlying causes of violence.
- Consider ethical implications and patient perspectives before implementing BWCs.
- BWCs should not be relied upon as a primary preventative measure for occupational violence.
Menichelli et al. (2024) – Policing universities: exploring the use of body-worn cameras by private campus security officers
Introduction
BWCs are widely used in law enforcement, but little is known about their use by private security, especially on university campuses.
Aim
To investigate how and why BWCs were introduced, how they are used, and with what outcomes by private campus security officers in the UK.
Research Question
How are BWCs adopted, used, and perceived by private campus security officers and university management, and what are the outcomes?
Methodology
- Semi-structured interviews with 13 campus security officers, 3 senior managers, 3 disciplinary officers, and 1 campus warden at a UK university
- Thematic analysis
Results
- BWCs were introduced to strengthen professionalism, credibility, and evidence collection.
- Use is infrequent and discretionary, mainly at night or during specific incidents.
- Footage is primarily used for disciplinary investigations, not for deterring violence.
- Officers felt BWCs offered protection against false claims but did not change their own behaviour.
- No evidence that BWCs reduced crime or disorder on campus.
Discussion
BWCs serve more as a tool for evidence and professionalisation than for violence prevention. Maintaining positive relationships with students is prioritised over frequent BWC use.
Gaps
- Limited research on BWC use by private security and on university campuses.
- Lack of student perspectives and broader sectoral data.
Conclusion
BWCs are not used as a primary violence prevention tool and have not reduced violence or disorder. Their main value is in evidence collection and supporting disciplinary processes.
Practical Implications
- BWCs should not be expected to prevent occupational violence in campus settings.
- Policies should focus on context-specific needs and maintain positive relationships.
- Further research is needed, especially including student perspectives.
Assaraf et al. (2024) – Behind the yellow sticker: paradoxical effects of a visual warning of body-worn cameras on the use of police force
Introduction
BWCs are proposed to reduce police use of force through deterrence, but the role of public awareness (e.g., visual warnings) is underexplored.
Aim
To test the effect of a visual warning (yellow sticker) on BWCs on the incidence of police use of force.
Research Question
Does a visual warning on BWCs reduce the use of force by police officers compared to BWCs without such a warning?
Methodology
- Six-month cluster-randomised controlled trial in Miami Beach, USA
- Police units assigned to BWCs with or without yellow stickers (“VIDEO & AUDIO” visual warning)
- Analysis of 28,393 police-public encounters
Results
- Officers with visually marked BWCs used force at a higher rate than those without.
- The presence of a visual warning increased the odds of use of force by 146.8%.
- The effect was more pronounced in proactive policing encounters.
Discussion
Visual warnings on BWCs may paradoxically increase use of force, possibly due to perceived threats to autonomy or lack of procedural fairness. The context and manner of BWC notification are critical.
Gaps
- Mechanisms remain speculative; further research needed on the psychological and procedural dynamics.
- Generalisability to other settings is uncertain.
Conclusion
Visual warnings on BWCs alone do not reduce, and may increase, use of force. Verbal notification and procedural fairness may be more effective.
Practical Implications
- Caution in relying on visual cues alone for BWC efficacy.
- Emphasise procedural justice and clear communication when deploying BWCs.
- Further research needed before implementing visual warnings as a violence prevention strategy.
Griffiths et al. (2024) – The use and impact of surveillance-based technology initiatives in inpatient and acute mental health settings: a systematic review
Introduction
Surveillance technologies, including BWCs, are increasingly used in mental health inpatient settings to improve safety and reduce costs, but their efficacy and ethical implications are debated.
Aim
To systematically review the implementation, experiences, and impact of surveillance technologies (including BWCs) in inpatient mental health settings.
Research Question
How are surveillance-based technologies (including BWCs) implemented and experienced in inpatient mental health settings, and what is their impact on outcomes such as violence, aggression, and safety?
Methodology
- Systematic review of 32 studies (quantitative, qualitative, mixed methods) on CCTV, vision-based monitoring, BWCs, GPS, and wearables
- Studies assessed for quality and conflicts of interest
Results
- Six studies focused on BWCs in UK mental health settings.
- Quantitative evidence on BWC impact on violence, aggression, and restrictive practices was inconsistent or weak.
- Some studies reported no significant reduction in violence/aggression or restrictive practices; others found mixed or context-dependent effects.
- Qualitative findings: staff and patient views on BWCs were mixed; concerns included privacy, ethics, and potential to undermine therapeutic relationships.
Discussion
There is insufficient evidence to support the use of BWCs as effective violence prevention tools in mental health inpatient settings. Ethical concerns and lack of robust, independent research are significant issues.
Gaps
- Lack of high-quality, independent studies.
- Underrepresentation of patient perspectives and lived experience.
- Limited research on long-term and unintended consequences.
Conclusion
Current evidence does not support BWCs as effective for improving safety or reducing violence in mental health inpatient settings. Further independent, co-produced research is needed.
Practical Implications
- BWCs should not be implemented as a primary violence prevention measure without stronger evidence.
- Policies must address ethical concerns, patient consent, and data protection.
- Stakeholder engagement, especially with patients, is essential in developing best practice guidance.
Ariel et al. (2016) – Wearing body cameras increases assaults against officers and does not reduce police use of force
Introduction
Police use of force and assaults against officers are major public concerns. BWCs have been proposed to reduce both, but robust evidence is limited.
Aim
To assess the effect of BWCs on police use of force and assaults against officers across multiple international sites.
Research Question
Do BWCs reduce police use of force and assaults against officers?
Methodology
- Prospective meta-analysis of 10 randomised controlled trials (RCTs) in 8 police forces across 6 countries
- Over 2 million citizens, 2.2 million officer-hours
- Outcomes: rates of police use of force and assaults against officers
Results
- No overall effect of BWCs on police use of force.
- BWCs led to a statistically significant increase in assaults against officers (about 14% higher than control).
- Heterogeneity across sites; some saw increased use of force, others saw reductions.
Discussion
The null result for use of force challenges the assumption that BWCs reduce force. The increase in assaults is unexpected; possible explanations include increased reporting, officers being less assertive, or BWCs escalating encounters.
Gaps
- Mechanisms behind increased assaults are unclear.
- Variation in definitions and reporting across jurisdictions.
- More research needed on officer discretion and context.
Conclusion
BWCs do not reduce police use of force on average and may increase assaults against officers. Caution is needed in implementing BWCs as a violence prevention tool.
Practical Implications
- BWCs should not be assumed to reduce violence or assaults.
- Implementation should consider local context and potential unintended consequences.
- Further research and careful policy design are needed.
Henstock & Ariel (2017) – Testing the Effects of Police Body-Born Cameras on Use of Force during Arrests
Introduction
BWCs are being rapidly adopted in policing, but controlled evidence of their effects is limited, especially outside the US.
Aim
To assess the effect of BWCs on police use of force in a large British police force.
Research Question
Do BWCs reduce the prevalence and severity of police use of force during arrests?
Methodology
- Six-month RCT in Birmingham South, UK
- 46 officers, 430 shifts (215 treatment, 215 control), 590 arrests
- Use of force measured via custody records, distinguishing between compliant and non-compliant handcuffing
Results
- Overall, 50% reduction in odds of use of force when BWCs are present (excluding compliant handcuffing).
- 35% reduction in overall weighted force in treatment vs. control.
- Effect concentrated in lower-level force (physical restraint, non-compliant handcuffing); no significant effect on higher-level force (batons, Taser, dogs).
- 40% increase in reporting of compliant handcuffing in BWC shifts, likely due to enhanced accountability.
Discussion
BWCs reduce lower-level force but not more aggressive tactics. Increased reporting of compliant handcuffing may reflect greater transparency. The effect depends on how “use of force” is defined.
Gaps
- Small sample for higher-level force incidents.
- No direct observation of conflict dynamics.
- Mechanisms (officer vs. suspect behaviour) remain unclear.
Conclusion
BWCs reduce use of force in lower-level encounters. Effects are conditional on definitions and context. BWCs increase transparency and accountability.
Practical Implications
- Policy should require officers to announce camera use.
- Definitions of force must be clear for evaluation.
- BWCs are most effective for less severe force and for increasing accountability.
Friis et al. (2019) – Ticket Inspectors in Action: Body-Worn Camera Analysis of Aggressive and Non-aggressive Passenger Encounters
Introduction
Workplace aggression is a significant hazard for public-facing employees, including ticket inspectors. The interactional dynamics of such aggression are underexplored.
Aim
To analyse how ticket inspector actions are associated with the risk of passenger aggression, using BWC footage.
Research Question
How do the actions of ticket inspectors during fining events influence the likelihood of passenger aggression?
Methodology
- Video analysis of 123 ticket fining events on public buses in Copenhagen, Denmark, recorded by BWCs
- Systematic coding of inspector and passenger actions
- Logistic regression to estimate risk factors for aggression
Results
- 13% of events involved passenger aggression.
- Inspector authority actions (e.g., assertiveness, mentioning police) and physical dominance (e.g., blocking movement) were associated with increased risk of aggression.
- Accommodating actions (e.g., showing sympathy) were associated with reduced risk.
- Aggression was more about interactional dynamics than individual characteristics.
Discussion
How inspectors interact with passengers shapes the risk of aggression. Training should focus on de-escalation and accommodation, not just enforcement. BWC footage is valuable for understanding and preventing workplace aggression.
Gaps
- Possible sample bias (inspectors may not record severe incidents).
- Limited data on personal characteristics and causal mechanisms.
Conclusion
Inspector behaviour, not just presence of BWCs, is key to preventing aggression. BWCs are useful for research and training, but not a standalone preventative measure.
Practical Implications
- Training should emphasise accommodating, non-dominant approaches.
- BWCs can inform situational prevention strategies and conflict management training.
- Policies should focus on employee behaviour, not just technology adoption.
Synthesis of All Documents
Introduction
Body-worn cameras (BWCs) have been widely adopted in policing, security, and public-facing roles with the aim of reducing violence, improving accountability, and deterring aggression. However, the evidence for their efficacy as a preventative measure for occupational violence is mixed and context dependent.
Aim
To synthesise the current research on the implementation, efficacy, and impact of BWCs as a preventative measure for occupational violence, with a focus on policing, public transport, and other public-facing roles.
Research Question
Do BWCs prevent occupational violence and aggression, and what are the mechanisms, experiences, and outcomes associated with their use?
Methodology
- Large-scale RCTs and meta-analyses in policing (UK, US, global)
- Video-based behavioural analysis in public transport (ticket inspectors)
- Qualitative and mixed-methods studies in mental health, campus security, and other settings
- Systematic reviews of surveillance technologies, including BWCs
Results
- In policing, BWCs do not reduce use of force on average and may increase assaults against officers.
- In some UK settings, BWCs reduce lower-level force (e.g., physical restraint) but not higher-level force (e.g., Taser, batons).
- In public transport, BWCs are valuable for research and training, but inspector behaviour (accommodation vs. dominance) is more important for preventing aggression than the presence of cameras.
- In mental health and campus security, evidence for violence prevention is weak or inconsistent; BWCs are used more for evidence and accountability than for prevention.
Discussion
The assumption that BWCs deter violence is not supported across settings. In some cases, BWCs may have unintended consequences, such as increased assaults or escalation of conflict. Training in de-escalation and accommodating behaviour is more effective for preventing aggression than technology alone.
Gaps
- More research is needed on mechanisms, context, and long-term effects.
- Underrepresentation of frontline perspectives and lived experience.
Conclusion
There is insufficient evidence to support BWCs as an effective standalone preventative measure for occupational violence. BWCs may reduce lower-level force and increase accountability but can also have unintended negative effects. The behaviour and training of staff are critical for violence prevention.
Practical Implications
- Do not rely on BWCs alone for violence prevention.
- Emphasise staff training in de-escalation and accommodating approaches.
- Ensure clear policies on camera use, reporting, and privacy.
- Engage stakeholders, including frontline staff and service users, in policy development.
Comparative Table: Efficacy of Body Worn Cameras for Preventing Occupational Violence
| Article & Year | Introduction | Aim | Research Question | Methodology | Results | Discussion | Gaps | Conclusion | Practical Implications | Efficacy for Preventing Occupational Violence |
| Wilson et al. (2023) | BWCs used in mental health wards; little research on effectiveness | Explore perspectives on BWCs in mental health settings | How do patients, staff, management perceive BWCs and their impact on violence? | Qualitative interviews (patients, staff, management) | No belief that BWCs deter violence; may undermine trust | Lack of evidence for deterrence; possible negative consequences | Lack of empirical evidence; ethical concerns | No support for BWCs as deterrent; possible role in safeguarding | Prioritise systemic interventions; consider ethics | No evidence for efficacy as a preventative measure |
| Menichelli et al. (2024) | BWCs in private security/campus; little research | Investigate BWC adoption, use, outcomes in campus security | How are BWCs adopted, used, perceived, and what are outcomes? | Qualitative interviews (security, management) | Used for evidence, not prevention; no reduction in violence | BWCs for evidence/professionalism, not prevention | Limited research; lack of student perspective | Not used as primary prevention; value in evidence | Don’t expect prevention; focus on context | No evidence for efficacy as a preventative measure |
| Assaraf et al. (2024) | BWCs proposed to reduce force; role of awareness unclear | Test effect of visual warning on use of force | Does visual warning reduce police use of force? | RCT (Miami Beach police, 28,393 encounters) | Visual warning increased use of force | Visual cues may escalate; context critical | Mechanisms speculative; generalisability | Visual warnings may increase force | Caution with visual cues; focus on procedural justice | No evidence for efficacy; may worsen outcomes |
| Griffiths et al. (2024) | Surveillance tech (incl. BWCs) in mental health; efficacy debated | Systematic review of surveillance tech in mental health | How are surveillance techs implemented, experienced, and what is impact? | Systematic review (32 studies) | Inconsistent/weak evidence for violence reduction | Insufficient evidence; ethical concerns | Lack of high-quality, independent studies | No support for BWCs as effective prevention | Don’t implement as primary prevention; address ethics | No robust evidence for efficacy |
| Ariel et al. (2016) | BWCs proposed to reduce force/assaults; limited evidence | Assess BWC effect on use of force and assaults | Do BWCs reduce use of force and assaults? | Meta-analysis of 10 RCTs (global) | No effect on force; increased assaults on officers | Null for force; assaults increased; context matters | Mechanisms unclear; reporting variation | No reduction in force; possible increase in assaults | Consider context; beware unintended effects | No efficacy; may increase risk to staff |
| Henstock & Ariel (2017) | BWCs rapidly adopted; little controlled evidence | Assess BWC effect on use of force (UK) | Do BWCs reduce prevalence/severity of force? | RCT (UK police, 430 shifts) | 50% reduction in lower-level force; no effect on high-level force | Reduces low-level force; increases transparency | Small sample for severe force; mechanisms unclear | Reduces low-level force; effect conditional | Announce camera use; clarify definitions | Some efficacy for low-level force only |
| Friis et al. (2019) | Aggression in public-facing roles; dynamics underexplored | Analyse inspector actions and risk of aggression | How do inspector actions affect passenger aggression? | BWC video analysis (123 events, buses) | Authority/dominance ↑ aggression; accommodation ↓ aggression | Staff behaviour more important than BWC presence | Sample bias; limited personal data | Staff behaviour key; BWCs useful for research/training | Train for accommodation/de-escalation | Efficacy depends on staff behaviour, not BWC alone |