Background: There is uncertainty as to whether and what extent occupational safety and health regulation and legislation enforcement activities, such as inspections, are effective and efficient to improve workers' health and safety. We use the term regulation to refer both to regulation and legislation.
Objectives: To assess the effects of occupational safety and health regulation enforcement tools for preventing occupational diseases and injuries.
Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PubMed), EMBASE (embase.com), CINAHL (EBSCO), PsycINFO (Ovid), OSH update, HeinOnline, Westlaw International, EconLit and Scopus from the inception of each database until January 2013. We also checked reference lists of included articles and contacted study authors to identify additional published, unpublished and ongoing studies.
Selection criteria: We included randomised controlled trials (RCTs), controlled before-after studies (CBAs), interrupted time series (ITS) and econometric panel studies of firms or workplaces evaluating inspections, warnings or orders, citations or fines, prosecution or firm closure by governmental representatives and if the outcomes were injuries, diseases or exposures.In addition, we included qualitative studies of workers' or employers' attitudes or beliefs towards enforcement tools.
Data collection and analysis: Pairs of authors independently extracted data on the main characteristics, the risk of bias and the effects of the interventions. We expressed intervention effects as risk ratios (RR) or mean differences (MD). We recalculated other effect measures into RRs or MDs. We combined the results of similar studies in a meta-analysis.
Main results: We located 23 studies: two RCTs with 1414 workplaces, two CBAs with 9903 workplaces, one ITS with six outcome measurements, 12 panel studies and six qualitative studies with 310 participants. Studies evaluated the effects of inspections in general and the effects of their consequences, such as penalties. Studies on the effects of prosecution, warnings or closure were not available or were of such quality that we could not include their results. The effect was measured on injury rates, on exposure to physical workload and on compliance with regulation, with a follow-up varying from one to four years. All studies had serious limitations and therefore the quality of the evidence was low to very low. The injury rates in the control groups varied across studies from 1 to 23 injuries per 100 person-years and compliance rates varied from 40% to 75% being compliant.The effects of inspections were inconsistent in seven studies: injury rates decreased or stayed at a similar level compared to no intervention at short and medium-term follow-up. In studies that found a decrease the effect was small with a 10% decrease of the injury rate. At long-term follow-up, in one study there was a significant decrease of 23% (95% confidence interval 8% to 23%) in injury rates and in another study a substantial decrease in accident rates, both compared to no intervention.First inspections, follow-up inspections, complaint and accident inspections resulted in higher compliance rates compared to the average effect of any other type of inspections.In small firms, inspections with citations or with more penalties could result in fewer injuries or more compliance in the short term but not in the medium term.Longer inspections and more frequent inspections probably do not result in more compliance.In two studies, there was no adverse effect of inspections on firm survival, employment or sales.Qualitative studies show that there is support for enforcement among workers. However, workers doubt if the inspections are effective because inspections are rare and violations can be temporarily fixed to mislead inspectors.
Authors' conclusions: There is evidence that inspections decrease injuries in the long term but not in the short term. The magnitude of the effect is uncertain. There are no studies that used chemical or physical exposures as outcome. Specific, focused inspections could have larger effects than inspections in general. The effect of fines and penalties is uncertain. The quality of the evidence is low to very low and therefore these conclusions are tentative and can be easily changed by better future studies. There is an urgent need for better designed evaluations, such as pragmatic randomised trials, to establish the effects of existing and novel enforcement methods, especially on exposure and disorders.