The designer shouldn't think of a simple dichotomy between errors and correct behavior; rather, the entire interaction should be treated as a cooperative endeavor between person and machine, one in which misconceptions can arise on either side.

It is relatively easy to design for the perfect cases, when everything goes right, or when all the information required is available in proper format

Readers always seem to think that the author has some control over the design of their books.

I think there is a tendency in science to measure what is measurable and to decide that what you cannot measure must be uninteresting.

In design it is important to shoe the effect of an action. ... Feedback is critical.

A challenge to the designers of the world: Make signs unnecessary.

To me, error analysis is the sweet spot for improvement.