Accident investigators historically have used hindsight to look at where people went wrong to reconstruct the human contribution to system failure; Dekker suggests a different approach.

Arguing that human error is systematically connected to aspects of people's tools and tasks, he suggests that understanding what went on in people's minds during an accident requires reconstructing the situation that the mind found itself in. His suggested methods, reminders, and pointers help investigators visualize how people's assessments and actions made sense at the time.