Vice-President, Comtech Services, Inc.

How usable is the design of your Web site? Jakob Nielsen recommends testing the user success rate to find out. He defines the user success rate as “the percentage of tasks that users complete correctly.” It’s a simple usability metric that will give your Web site design a bottom-line usability score. Ask your users to perform a list of tasks and give them either a pass or fail grade on each task. Give them partial credit on tasks they are able to partially complete. Average their scores to find your user success rate. Nielsen finds that most Web sites have a user success rate of less than 50%.

Read Jakob Nielsen’s Alertbox from February 18, 2001