The Field Guide to Understanding 'Human Error'

by Sidney Dekker

If you look, for a moment, at the psychological research underlying all this, there are actually two ways in which your understanding of a past situation gets influenced: • The hindsight bias. Finding out about an outcome increases the estimate we make about its likelihood. In other words, as a retrospective reviewer who knows the outcome of an event, you exaggerate your own ability to predict and prevent the outcome—while not even being aware of that bias.2 • The outcome bias. Once you know the outcome, it changes your evaluation of decisions that led up to it. If the outcome is bad, then you are not only more willing to judge the decisions, but also more likely to judge them more harshly.3