Textbook of Usability

b. 1938, United Kingdom · Emeritus professor at the University of Manchester

Also known as: James Reason, James T. Reason

James T. Reason spent his career at the University of Manchester developing the most widely-used theoretical framework for understanding how accidents happen in complex socio-technical systems. His 1990 book Human Error and the 2000 BMJ paper Human Error: Models and Management set out the Swiss cheese model: hazards pass through a series of defensive layers (procedures, training, automation, supervision), each of which has holes (latent conditions); accidents occur when the holes momentarily line up.

The model shifts attention from the sharp-end operator who pulled the lever to the latent organisational and design conditions that allowed the lever to be pulled, and is the dominant framework in healthcare, aviation and nuclear safety. Reason's distinction between active failures (errors at the point of action) and latent conditions (design and management decisions whose consequences appear later) is now standard vocabulary in safety analysis.