3 methods for increasing UX quality by exploring and testing diverse design ideas work even better when you use them together.| Nielsen Norman Group
Using Discount Usability Engineering to Penetrate the Intimidation Barrier,' paper by Jakob Nielsen on simpler and cheaper ways to a better UI;with examples of fast usability projects.| Nielsen Norman Group
Testing ever-more users in card sorting has diminishing returns, but test at least 15 users -- 3 times more than you would in traditional usability tests.| Nielsen Norman Group
When collecting usability metrics, testing with 20 users typically offers a reasonably tight confidence interval.| Nielsen Norman Group
The answer is 5, except when it's not. Most arguments for using more test participants are wrong, but some tests should be bigger and some smaller.| Nielsen Norman Group