Using Safety-I, II, and III to level up patient safety

This review provides clinicians with an introduction to the theories underlying safety-I, II, and III. These are concepts that have recently been adapted to healthcare and are growing in popularity among patient safety experts. Clinicians will be encountering patient safety interventions and analyses rooted in these theories, making an understanding of the safety science behind them important.

There is a growing body of literature analyzing safety-I, II, and III in healthcare as well as multiple recently published applied case studies.

Safety-I, II, and III are complementary ways of considering how accidents occur and how systems can build safety. Safety-I assumes that accidents occur through linear chains of events, prompting searches for root causes of accidents. Safety-II is grounded in resilience engineering and posits that accidents occur due to variability, but variability can also be protective as people prevent harm from reaching patients. Safety-III assumes that safety emerges from the interactions of the people, software, and hardware in the system as they work to control their behavior within safe bounds. These three unique lenses on safety offer different lessons learned from accidents and different strategies to promote patient safety.