Home Course Concepts About

Accident debriefing bingo
Postmortems and distancing through differencing


Have you ever participated in an event investigation or post-incident postmortem and heard participants say

That wouldn’t have happened to us…

This is a form of denial, and is common after accidents. Next time you’re in that situation, try playing a game of Accident debriefing bingo. See how long it takes to check a complete row or column of postulated “reasons” why your organization or system wouldn’t be affected by this kind of problem.

Accident Bingo
A game to play next time you participate in an event investigation debriefing

Learning after an accident is subject to multiple barriers, one of which is denial. It is based on a “distancing through differencing” phenomenon [Cook and Woods 2006], in which people attempt to identify reasons for which the event would never occur on their site.In psychology, social distance describes the amount of separation between different groups in society; it’s a measure of “us”/“them” differences.

This is a natural psychological tendency: accepting that an accident could happen to us is quite frightening, and (for safety specialists) calls into question our professional competencies.


The Blayais nuclear power plant in France, located on an estuary near Bordeaux, was affected by a severe flooding event in 1999. Tide and winds from a storm led to water levels higher than the protective dikes around the facility, and disabled the plant’s offsite power supply as well as a number of safety systems.

Multiple lessons were learned from this event, leading to changes to a number of other nuclear power plants in France (reassessment of the validity of flood models and of the strength of protective dikes, organization of emergency response). However, these measures were not adopted by all countries operating nuclear power plants.

Denial is contrary to the preoccupation with failure encouraged by HRO researchers.


Cook, Richard I., and David D. Woods. 2006. Distancing through differencing: An obstacle to organizational learning following accidents. In Resilience Engineering: Concepts and Precepts, edited by Erik Hollnagel, David D. Woods, and Nancy Leveson. Ashgate, ISBN: 978-0754646419.