Needham 2005.

Study characteristics
Methods	Cluster‐randomized controlled trial Cluster sample: six psychiatric wards of 87 invited, with 3 wards randomly assigned as intervention and control sites. All 87 acute psychiatric wards in the German‐speaking portion of Switzerland were invited to participate in the study. The 6 wards recruited for this study agreed to waiting list randomization. Three wards were randomly allocated to the intervention group and the remaining 3 to the control group. Treatment of missing data not reported Study location/s German‐speaking portion of Switzerland Study setting/s 6 acute psychiatric wards, with 3 randomly allocated to the intervention group and 3 to the control group Withdrawals None listed
Participants	Non‐random sample of participants:n = 58 (30 intervention, 28 control) Health worker type/s Mental health nurses Total number, number of health worker type subpopulations and proportions (%) 58 total: 30 in intervention wards, 28 in control wards Mean age or age range 36.47 in intervention, 39.21 in control Gender 18 female, 12 male in intervention; 14 female, 14 male in control Workplace/s (e.g. mental health, emergency department) Acute psychiatric wards Work setting/s (e.g. hospital inpatient, hospital outpatient, community) Not specified Work sector/s (e.g. public, private, non‐government) Not specified Inclusion and exclusion criteria All 114 nurses working on the 6 participating wards were invited. No exclusion criteria were stated
Interventions	Face‐to‐face program 20 ×50‐minute lessons over 5 consecutive days Description of intervention and co‐interventions (especially noting whether bundled with other organizational interventions) 20 lessons, each lasting 50 minutes, administered by trained psychiatric nurses on 5 consecutive days Targeted knowledge, attitudes, and skills Types and causes of aggression, the genesis of aggression, reflection on one’s own aggressive components, theory on the various stages of aggressive incidents, behavior during aggressive situations, types of conflict management, communication and interaction, post‐aggression procedures, workplace safety, prevention of aggression, breakaway techniques, and role‐play Comparison No training. Training was, however, received by the control group after completion of the study Content of both intervention and control conditions, and co‐interventions As above. The control group received education and training after completion of the study Duration 5 consecutive days Intensity (e.g. frequency or levels of intervention) Intervention was 20 × 50‐minute lessons Number commencing 58: 30 in intervention wards, 28 in control wards Number completing Not specified Adherence to protocol Some attrition with persons not completing the questionnaire in both rounds
Outcomes	Perception of aggression (primary) Tolerance toward patient aggression Adverse emotions in dealing with aggressive patients Measurement instruments used and validation status (e.g. reported / not reported) Short version of the Perception of Aggression Scale (POAS‐S)—validated, not reported Tolerance Scale—not validated Impact of Patient Aggression on Carers Scale (IMPACS)—validated, Cronbach’s alphas Time points reported Pre‐intervention (T1) Intervention over 5 days Post‐intervention at 3 months (T2) Controlling for biasing or confounding effects of co‐interventions Not specified Time points at which primary and secondary outcomes were collected and categorization to short‐term (6 months and less), medium‐term (more than 6 months up to 12 months), and long‐term (> 12 months) follow‐up Short‐term: 3 months
Notes	Study authors and email address of corresponding author I. Needham (needham@bluewin.ch), C. Abderhalden, R.J.G. Halfens, T. Dassen, H.J. Haug, J.E. Fischer Funding for study Grant # 3251B0‐1‐710 of the Swiss National Science Foundation Notable conflicts of interest of study authors None specified
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information to permit judgment of "low risk" or "high risk"
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgment of "low risk" or "high risk"
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgment of "low risk" or "high risk"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgment of "low risk" or "high risk"
Incomplete outcome data (attrition bias) All outcomes	High risk	Poor response rates to outcome measure—no explanation for attrition nor accounting for its impact provided
Selective reporting (reporting bias)	Low risk	Pre‐specified measures were reported in sufficient detail
Other bias	High risk	Small samples of participants. Results reported for individual participants rather than by cluster