New health & safety research shows value of certification

January 12, 2022

Research from academics at Harvard Business School and Duke University has just been released, providing significant research findings concerning management system certification.

The  research explored the health and safety performance of companies who were certified to the OHSAS 18001 health & safety standard. This standard is the precursor and inspiration behind ISO’s (International Organization for Standardization) highly successful ISO 45001 standard, which in its brief three years, has seen over a quarter of a million sites certified, making it ISO’s third most popular standard.

To investigate the performance of OHSAS 18001 certified organisations, the researchers examined US Bureau of Labor Statistics data, reviewing the injury data from companies certified to OHSAS 18001 and ‘comparable non-adopters’. The research made two fundamental conclusions:

  1. ‘The OHSAS 18001 standard attracts establishments with fewer injury and illness cases than comparable non-adopters’. This is described as ‘a selection effect’
  2. ‘Certification leads to subsequent declines in such (injury and illness) cases. This is a ‘treatment effect’.

These particularly significant research findings provide clear evidence of OHSAS 18001 adopters exhibiting superior health and safety performance. The first conclusion shows that this better performance is already exhibited by organisations and the second shows that this performance increases after certification.

Significantly, the research quantifies the impact, with the conclusion that, ‘OHSAS certification reduces all illness and injury cases by 20 percent’. This highly positive result is strengthened by the wide range of establishments analysed. These covered a broad range of industries and economic activities, from numerous types of service sector establishments to various in the manufacturing sector, in total covering 29 different NAICS (North American Industry Classification System) codes.

The paper concludes that the findings, ‘give credence to the effectiveness of management system standards as a tool to improve performance and encourages the creation and adoption of similar management system standards across other performance dimensions.’

As usual for a research paper such as this, the working paper is currently being subjected to the peer review process, and may be subjected to revisions before becoming a published peer-reviewed article.

The abstract for the paper and the formal citation are:

‘Millions of companies around the world have adopted management system standards to both convey superior operational performance and to improve their operations. Yet because these standards impose requirements on operational processes and procedures, it is largely unknown whether adopting these standards actually bears any relationship with operational performance. We examine this question in the context of the OHSAS 18001 Occupational Health and Safety Management system standard. Analyzing proprietary certification data from some of the world’s largest certification companies and injury microdata from the U.S. Bureau of Labor Statistics, we find that U.S. establishments certified to the OHSAS 18001 standard indeed tend to be safer workplaces. The OHSAS 18001 standard attracts establishments with fewer injury and illness cases than comparable non-adopters (a selection effect), and certification leads to subsequent declines in such cases (a treatment effect). These results provide rare evidence the adoption of a management system standard serves both as a credible indicator of superior operational performance, as well as a means to improve performance.’

Citation: Viswanathan, Kala and Johnson, Matthew and Toffel, Michael W., Do Management System Standards Indicate Superior Performance? Evidence from the OHSAS 18001 Occupational Health and Safety Standard (December 5, 2021). Harvard Business School Technology & Operations Mgt. Unit Working Paper No. 22-042, Available at SSRN: or