: Measuring exactly how long it takes a user to complete a purchase and if that time is within acceptable business limits.

: Traditionally, usability was seen as a purely qualitative field. This book challenges that by showing how common design impacts—like conversions, completion rates, and perceived satisfaction—can and should be measured.

Ultimately, the book’s "resolution" is to empower researchers to communicate results in "plain English" to business leaders, ensuring that user-centric changes are seen as valuable investments rather than subjective preferences.

: A core part of the story involves Confidence Intervals and Margin of Error . It teaches researchers how to answer critical business questions like, "Can we be 95% sure that at least 70% of users can complete this task?".