Do Safety Management System Standards Indicate Safer Operations? Evidence from the OHSAS 18001 Occupational Health and Safety Standard

Problem definition: Given the enormous disruptions and costs of occupational injuries, companies and buyers are increasingly looking to voluntary occupational health and safety standards to improve worker safety. Yet because these standards only require implementing certain processes and procedures, it is largely unknown whether certification actually conveys superior safety performance. We examine this relationship in the context of the OHSAS 18001 Occupational Health and Safety Management system standard. Methodology/results: We analyze proprietary certification data over 1995 to 2016 from some of the world’s largest certification bodies and establishment-level injury data from the U.S. Bureau of Labor Statistics, and find that U.S. establishments certified to OHSAS 18001 tend to be safer workplaces. OHSAS 18001 attracts establishments with fewer injury and illness cases than comparable establishments (a selection effect). Using propensity score matching and a difference-in-differences approach, we estimate that OHSAS 18001 certification reduces the total number of illness and injury cases by 20 percent and illness and injury cases associated with job transfers or restrictions by 24 percent. Managerial implications: Our results indicate that becoming certified to a safety management standard can lead to meaningful improvements in workplace safety, and that OHSAS 18001 certification is a credible indicator of superior average safety performance, an important insight for buyers and suppliers. Given that OHSAS 18001 is the basis for the newer ISO 45001 standard that has quickly become the world’s third-most popular management system standard, this study provides promising evidence that ISO 45001 will also prove effective in distinguishing safer workplaces.