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Decremental and Incremental Safety Cultures: Safety-I and Safety-II Revisited

CRC Press publishes Erik Hollnagel's Decremental and Incremental Safety Cultures: Safety-I and Safety-II Revisited on 25 September 2026. The 264-page book returns to the argument of Safety-I and Safety-II (2014) and treats culture as a set of practices rather than a maturity score. Where a decremental culture tries to make work safer by subtracting failures, an incremental culture tries to raise the share of work that goes as intended.

Fourteen chapters move from a primer on Safety-I and Safety-II through the apparent ambiguity of safety, seven biases of safety thinking, the inevitability of accidents, and what Hollnagel calls the semantic non-sense of safety. Later chapters take up the seven stages of safety thinking, atomistic accident thinking, and the complexity delusion: the habit of treating complexity as a property to be tamed by more analysis, rather than as a condition of everyday work.

Two consecutive chapters on safety pragmatism and safety solutionism will be familiar to anyone who has watched organisations reach for a new method, a new indicator, or a new software tool whenever the last one disappointed. The book then asks a practical question: how to improve the ratio of acceptable to unacceptable outcomes. That question leads into decremental safety practices, incremental safety practices, and the Resilient Performance Enhancement Toolkit (RPET).

This is a different object from the March 2025 note on changing from a decremental to an incremental safety culture. That note was a short argument about the four potentials to respond, monitor, learn, and anticipate. The 2026 book is the longer revisit: history, language, biases, and a toolkit. It also sits beside From Safety to Safely, which asks organisations to manage safely as a capability rather than to defend "safety" as a noun.

Readers who already work with Systemic Potentials Management will recognise the same direction: stop counting only what went wrong, and start building the conditions under which everyday work succeeds. RPET is presented as a way to do that without turning resilience into another slogan or another audit checklist.

Further reading: CRC Press / Routledge: Decremental and Incremental Safety Cultures · Safety-I and Safety-II (2014) · Resilience Engineering Guide