From Safety-I to Safety-II: A White Paper


Most people think of safety as the absence of accidents and incidents (or as an acceptable level of risk). In this perspective, which we term Safety-I, safety is defined as a state where as few things as possible go wrong. A Safety-I approach presumes that things go wrong because of identifiable failures or malfunctions of specific components: technology, procedures, the human workers and the organisations in which they are embedded. Humans—acting alone or collectively—are therefore viewed predominantly as a liability or hazard, principally because they are the most variable of these components. The purpose of accident investigation in Safety-I is to identify the causes and contributory factors of adverse outcomes, while risk assessment aims to determine their likelihood. The safety management principle is to respond when something happens or is categorised as an unacceptable risk, usually by trying to eliminate causes or improve barriers, or both. This view of safety became widespread in the safety critical industries (nuclear, aviation, etc.) between the 1960s and 1980s. At that time performance demands were significantly lower than today and systems simpler and less interdependent. Crucially, the Safety-I view does not stop to consider why human performance practically always goes right. Safety management should therefore move from ensuring that ‘as few things as possible go wrong’ to ensuring that ‘as many things as possible go right’. We call this perspective Safety-II; it relates to the system’s ability to succeed under varying conditions. A Safety-II approach assumes that everyday performance variability provides the adaptations that are needed to respond to varying conditions, and hence is the reason why things go right.  This White Paper helps explains the key differences between, and implications of, the two ways of thinking about safety. 


  • Executive Summary
  • Background: The World Has Changed
  • Safety-I
  • The Manifestations of Safety-I: Looking at What Goes Wrong
  • The Mechanisms of Safety-I
  • The Foundation of Safety-I
  • The Changing World of Health Care
  • The Reasons Why Things Work - Again
  • Safety-II
  • The Foundation of Safety-II: Emergence Rather Than Causality
  • The Manifestations of Safety-II: Things That Go Right
  • The Way Ahead
  • Transitioning to Safety-II
  • Conclusion
  • Epilogue
  • References
  • Glossary


Contact Person/Organization: 


  • Professor Erik Hollnagel, University of Southern Denmark, Institute for Regional Health Research (IRS), Denmark Center for Quality, Region of Southern Denmark
  • Professor Robert L Wears, University of Florida Health Science Center Jacksonville, United States of America
  • Professor Jeffrey Braithwaite, Australian Institute of Health Innovation, Macquarie University, Australia 

Type of Tool:

Publication Date: 

Safety-I and Safety-II - Professor Erik Hollnagel