Abstract: Seventeen studies (14 ITS and 3 CBA studies) met the inclusion criteria in this updated version of the review. The ITS studies evaluated the effects of: introducing or changing regulations that laid down safety and health requirements for the construction sites (nine studies), a safety campaign (two studies), a drug-free workplace programme (one study), a training programme (one study), and safety inspections (one study) on fatal and non-fatal occupational injuries. One CBA study evaluated the introduction of occupational health services such as risk assessment and health surveillance, one evaluated a training programme and one evaluated the effect of a subsidy for upgrading to safer scaffoldings. The overall risk of bias of most of the included studies was high, as it was uncertain for the ITS studies whether the intervention was independent from other changes and thus could be regarded as the main reason of change in the outcome. Therefore, we rated the quality of the evidence as very low for all comparisons. Compulsory interventions Regulatory interventions at national or branch level may or may not have an initial effect (effect size (ES) of −0.33; 95% confidence interval (CI) −2.08 to 1.41) and may or may not have a sustained effect (ES −0.03; 95% CI −0.30 to 0.24) on fatal and non-fatal injuries (9 ITS studies) due to highly inconsistent results (I² = 98%). Inspections may or may not have an effect on non-fatal injuries (ES 0.07; 95% CI −2.83 to 2.97; 1 ITS study). Educational interventions Safety training interventions may result in no significant reduction of non-fatal injuries (1 ITS study and 1 CBA study). Informational interventions We found no studies that had evaluated informational interventions alone such as campaigns for risk communication. Persuasive interventions We found no studies that had evaluated persuasive interventions alone such as peer feedback on workplace actions to increase acceptance of safe working methods. Facilitative interventions Monetary subsidies to companies may lead to a greater decrease in non-fatal injuries from falls to a lower level than no subsidies (risk ratio (RR) at follow-up: 0.93; 95% CI 0.30 to 2.91 from RR 3.89 at baseline; 1 CBA study). Multifaceted interventions A safety campaign intervention may result in an initial (ES −1.82; 95% CI −2.90 to −0.74) and sustained (ES −1.30; 95% CI −1.79 to −0.81) decrease in injuries at the company level (1 ITS study), but not at the regional level (1 ITS study). A multifaceted drug-free workplace programme at the company level may reduce non-fatal injuries in the year following implementation by −7.6 per 100 person-years (95% CI −11.2 to −4.0) and in the years thereafter by −2.0 per 100 person-years (95% CI −3.5 to −0.5) (1 ITS study). Introducing occupational health services may result in no decrease in fatal or non-fatal injuries (one CBA study). The vast majority of interventions to adopt safety measures recommended by standard texts on safety, consultants and safety courses have not been adequately evaluated. There is very low-quality evidence that introducing regulations as such may or may not result in a decrease in fatal and non-fatal injuries. There is also very low-quality evidence that regionally oriented safety campaigns, training, inspections or the introduction of occupational health services may not reduce non-fatal injuries in construction companies. There is very low-quality evidence that company-oriented safety interventions such as a multifaceted safety campaign, a multifaceted drug workplace programme and subsidies for replacement of scaffoldings may reduce non-fatal injuries among construction workers. More studies, preferably cluster-randomised controlled trials, are needed to evaluate different strategies to increase the employers' and workers' adherence to the safety measures prescribed by regulation.

Plain-language summary: We conducted a systematic search of the literature on preventing occupational injuries among construction workers. We included 17 studies in this updated review, rating the evidence as very low quality. Multifaceted interventions and company incentives for upgrading equipment may be effective in reducing injury. However, an evidence base is still needed for the vast majority of safety measures that safety manuals, consultants and safety courses routinely recommend. What was studied in the review? We looked at different types of workplace interventions, including the introduction of new regulations, safety campaigns, training, inspections, occupational health services, and company subsidies. We evaluated the quality of the studies and the effectiveness of interventions, rating the evidence as very low quality. What are the main results of the review? Introducing regulations alone may or may not be effective for preventing non-fatal and fatal injuries in construction workers. Regionally oriented interventions such as a safety campaigns, training, inspections or occupational health services may not be effective for reducing non-fatal injuries in construction workers. However, a multifaceted safety campaign and a multifaceted drug-free workplace programme at the company level, along with subsidies for replacement of scaffoldings, may be effective in reducing non-fatal injuries. Additional strategies are needed to increase the employers' and workers' adherence to the safety measures that are prescribed by regulation. How up-to-date is this review? We searched for studies that had been published up to 1 April 2017.