Summary of findings 1. Summary of findings.

Education and training compared with no training for preventing and minimizing workplace aggression directed toward healthcare workers
Patients or population: healthcare workers Setting: workplace Intervention: violence prevention training Comparison: no training
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No. of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	No training	Violence prevention training
1.1 Number of episodes of aggression (CRCT)—short‐term follow‐up Assessed with: Assault logs (lower scores = better outcomes) Follow‐up at 2 weeks		SMD 0.33 SD lower (1.27 lower to 0.61 higher)		49 (2 CRCTs)	⊕⊝⊝⊝a,b,c very low
1.2 Number of episodes of aggression (CBA)—short‐term follow‐up Assessed with: Reports of incidents of aggression (lower outcomes = better outcomes) Follow‐up at 28 days	8 per 100	19 per 100	RR 2.30 (0.97 to 5.42)	155 (1 CBA)
1.3 Number of episodes of aggression (CBA)—short‐term follow‐up Assessed with: Workplace Violence Questionnaire and Demographics tool (lower outcomes = better outcomes) Follow‐up at 6 months		SMD 1.24 SD lower (2.16 lower to 0.33 lower)		23 (1 CBA)
1.4 Number of episodes of aggression (CRCT)—long‐term follow‐up Assessed with: Percentage of participants who reported having been the victim of aggression (yes/no) at follow‐up Follow‐up at 12 months	58 per 100	66 per 100 (54 to 76)	RR 1.14 (0.95 to 1.37)	291 (1 CRCT)	⊕⊕⊝⊝d low
2.1 Knowledge about aggression (RCT/CRCT)—short‐term follow‐up Assessed with: Knowledge test (higher outcomes = better outcomes) Follow‐up at 1 day to 8 weeks		SMD 0.86 SD higher (0.34 higher to 1.38 higher)		62 (1 RCT)	⊕⊕⊝⊝b,f low
2.2 Knowledge about aggression(RCT/CRCT)—long‐term follow‐up Assessed with: Questions regarding self‐perceived improvements in knowledge Follow‐up at 12 months	63 per 100	71 per 100 (65 to 77)	RR 1.26 (0.90 to 1.75)	291 (1 CRCT)	⊕⊝⊝⊝b,d,g very low
3. Attitudes (RCT/CRCT)—short‐term follow‐up Assessed with: Perception of Aggression Scale, Tolerance to Aggression Scale, responses to questions about attitudes toward aggression (higher = better outcomes) Follow‐up range: 1 day to 3 months		SMD 0.59 SD higher (0.24 higher to 0.94 higher)		683 (2 CRCTs and 3 RCTs)	⊕⊝⊝⊝e,h very low
4. Skills (RCT/CRCT)—short‐term follow‐up Assessed with: Unspecified questionnaire measuring empathy (higher score = better outcomes) Follow‐up at 8 weeks		SMD 0.21 SD higher (0.07 lower to 0.49 higher)		198 (1 RCT and 1 CRCT)	⊕⊝⊝⊝b,j very low
5. Adverse personal outcomes (RCT/CRCT)—short‐term follow‐up Assessed with: IMPACS Questionnaire (lower scores = better outcomes) Follow‐up at 3 months		SMD 0.31 SD lower (1.02 lower to 0.40 higher)		31 (1 RCT)	⊕⊝⊝⊝b,k  very low
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CBA: controlled before and after study; CI: confidence interval; CRCT: cluster‐randomized clinical trial; MD: mean difference; RCT: randomized controlled trial; RR: risk ratio; SMD: standardized mean difference.
GRADE Working Group grades of evidence. High quality: further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate.
aDowngraded two levels for high risk of performance and selection bias (Fitzwater 2002). Unclear risk of selection and performance bias (Irvine 2012b). bDowngraded one level for imprecision due to small sample size and the resulting estimate including little to no effect. cEvidence from CBA studies was downgraded two levels for high risk of performance and selection bias (Whittington 1996; Anderson 2006), and by one level for imprecision due to the resulting estimate including little to no effect and small sample size. dDowngraded two levels due to unclear risk of performance and selection bias (Arnetz 2000). eDowngraded one level for inconsistency and significant heterogeneity. fDowngraded one level due to unclear risk of performance bias (Irvine 2007). gDowngraded one level due to indirectness. hDowngraded two levels due to high risk of attrition bias (Needham 2005), as well as unclear risk of performance bias (Irvine 2007; Irvine 2012a; Irvine 2012b). iDowngraded one level for high risk of performance and selection bias (Fitzwater 2002), as well as unclear risk of performance bias (Irvine 2007; Irvine 2012a; Irvine 2012b). jDowngraded two levels due to unclear risk of selection bias (Irvine 2012a; Irvine 2012b), as well as performance bias (Irvine 2012b). kDowngraded two levels due to high risk of attrition bias (Needham 2005).