Progressive disclosure defers advanced or rarely used features to a secondary screen, making applications easier to learn and less error-prone.| Nielsen Norman Group
1073 design guidelines to improve conversion rates and customers' shopping experience. 13 volumes, with more than 3100 screenshots that worked or failed in user testing.| Nielsen Norman Group
Depending on how representative designers are of the target audience, a project might need more or less user testing. Still, usability concerns never go away completely.| Nielsen Norman Group