Heuristic Evaluation
Heuristic Evaluation is used to identify usability problems with an interface by judging it's compliance with known usability principles. It's fast, easy and can be done at home. The basic idea of heuristic evaluation is to put yourself in the mindset of someone using the system, and ask yourself questions like:
- Is it obvious what's happening at each point?
- Is the system efficient to use?
- Is it visually attractive?
- Are any errors well-explained and easy to recover from?
Usability Heuristics
Usability heuristics are rules for judging whether an interface is usable. You should become familiar with at least the basic heuristics before conducting an evaluation. Ten usability heuristics is a good place to start. You can also try looking at this Interactive Heuristic Evaluation Toolkit or try selecting your own heuristics from a longer list.
Severity Ratings
Sometimes, it is useful to order the usability problems you have found according to severity. Nielsen suggests looking at three areas:
How frequently the problem occurs.
How much of an impact it has on the user. How easily can the user get around it?
How persistent the problem is. Does it repeatedly bother the user, or can they overcome it after learning about it?
It is recommended to get severity ratings from several (three is a good rule-of-thumb) people, and to then average them.
Useful Links
A brief introduction to heuristic evaluation by Jakob Nielsen
Jakob Nielsen's heuristic evaluation page
Heuristic evaluation at the Usability Body of Knowledge (including a how-to)