Background Bullying has been identified as one of the leading workplace stressors, with adverse consequences for the individual employee, groups of employees, and whole organisations. Employees who have been bullied have lower levels of job satisfaction, higher levels of anxiety and depression, and are more likely to leave their place of work. Organisations face increased risk of skill depletion and absenteeism, leading to loss of profit, potential legal fees, and tribunal cases. It is unclear to what extent these risks can be addressed through interventions to prevent bullying. Objectives To explore the effectiveness of workplace interventions to prevent bullying in the workplace. Search methods We searched: the Cochrane Work Group Trials Register (August 2014); Cochrane Central Register of Controlled Trials (CENTRAL; TheCochrane Library 2016, issue 1); PUBMED(1946 to January 2016); EMBASE (1980 to January 2016); PsycINFO(1967 to January 2016); Cumulative Index to Nursing and AlliedHealth Literature (CINAHL Plus; 1937 to January 2016); International Bibliography of the Social Sciences (IBSS; 1951 to January 2016); Applied Social Sciences Index and Abstracts (ASSIA; 1987 to January 2016); ABI Global (earliest record to January 2016); Business Source Premier (BSP; earliest record to January 2016); OpenGrey (previously known as OpenSIGLE-System for Information on Grey Literature in Europe; 1980 to December 2014); and reference lists of articles. Selection criteria Randomised and cluster-randomised controlled trials of employee-directed interventions, controlled before and after studies, and interrupted time-series studies of interventions of any type, aimed at preventing bullying in the workplace, targeted at an individual employee, a group of employees, or an organisation. Data collection and analysis Three authors independently screened and selected studies. We extracted data from included studies on victimisation, perpetration, and absenteeism associated with workplace bullying. We contacted study authors to gather additional data. We used the internal validity items from the Downs and Black quality assessment tool to evaluate included studies' risk of bias. Main results Five studies met the inclusion criteria. They had altogether 4116 participants. They were underpinned by theory and measured behaviour change in relation to bullying and related absenteeism. The included studies measured the effectiveness of interventions on the number of cases of self-reported bullying either as perpetrator or victim or both. Some studies referred to bullying using common synonyms such as mobbing and incivility and antonyms such as civility. Organisational/employer level interventions Two studies with 2969 participants found that the Civility, Respect, and Engagement in the Workforce (CREW) intervention produced a small increase in civility that translates to a 5% increase from baseline to follow-up, measured at 6 to 12 months (mean difference (MD) 0.17; 95% CI 0.07 to 0.28). One of the two studies reported that the CREW intervention produced a small decrease in supervisor incivility victimisation (MD -0.17; 95% CI -0.33 to -0.01) but not in co-worker incivility victimisation (MD -0.08; 95% CI -0.22 to 0.08) or in self-reported incivility perpetration (MD -0.05 95% CI -0.15 to 0.05). The study did find a decrease in the number of days absent during the previous month (MD -0.63; 95% CI -0.92 to -0.34) at 6-month follow-up. Individual/job interface level interventions One controlled before-after study with 49 participants compared expressive writing with a control writing exercise at two weeks followup. Participants in the intervention arm scored significantly lower on bullying measured as incivility perpetration (MD -3.52; 95% CI -6.24 to -0.80). There was no difference in bullying measured as incivility victimisation (MD -3.30 95% CI -6.89 to 0.29). One controlled before-after study with 60 employees who had learning disabilities compared a cognitive-behavioural intervention with no intervention. There was no significant difference in bullying victimisation after the intervention (risk ratio (RR) 0.55; 95% CI 0.24 to 1.25), or at the three-month follow-up (RR 0.49; 95% CI 0.21 to 1.15), nor was there a significant difference in bullying perpetration following the intervention (RR 0.64; 95% CI 0.27 to 1.54), or at the three-month follow-up (RR 0.69; 95% CI 0.26 to 1.81). Multilevel Interventions A five-site cluster-RCT with 1041 participants compared the effectiveness of combinations of policy communication, stress management training, and negative behaviours awareness training. The authors reported that bullying victimisation did not change (13.6% before intervention and 14.3% following intervention). The authors reported insufficient data for us to conduct our own analysis. Due to high risk of bias and imprecision, we graded the evidence for all outcomes as very low quality. Authors' conclusions There is very low quality evidence that organisational and individual interventions may prevent bullying behaviours in the workplace. We need large well-designed controlled trials of bullying prevention interventions operating on the levels of society/policy, organisation/employer, job/task and individual/job interface. Future studies should employ validated and reliable outcome measures of bullying and a minimum of 6 months follow-up.
