Error Handling

A huge part of any interaction design project involves dealing with "user error"--what does the system do when people make mistakes, and what can the system do to prevent those mistakes from happening in the first place?

Prevention

The first and best defense against erros is to design the system so that erros can't happen. Unfortunately, it's not quite so easy to make most user errors impossible.

Correction

The next best thing to making errors impossible is to make them merely difficult. But even still, some errors are bound to happen. At this point, the system should do what it can to figure out the error and fix it. In some cases, the system can figure out the error and fix it.

Recovery

Helpful error messages and well-designed interfaced can help users catch many kinds of errors after they've happened. But some user action may not appear to be errors until it's too late even for the system to catch them. In these cases, the system should provide a way for users to recover from the error.