The Field Guide to Understanding Human Error, 2nd Edition

1 The Bad Apple Theory

There are basically two ways of looking at human error. The first view is known as the Old View, or The Bad Apple Theory. It maintains that:

• Complex systems would be fine, were it not for the erratic behavior of some unreliable people (Bad Apples) in it;
• Human errors cause accidents: humans are the dominant contributor to more than two thirds of them;
• Failures come as unpleasant surprises. They are unexpected and do not belong in the system. Failures are introduced to the system only through the inherent unreliability of people.

This chapter is about the first view. The second is about a contrasting view, known as the New View. The rest of the book helps you avoid the Old View and apply the New View to your understanding ...