Katie Sherwin is a Senior User Experience Specialist with Nielsen Norman Group. She specializes in helping organizations utilize principles of user-centered design and strategic communication to achieve their goals.
User research with prospective university students, ranging from kids still in high school to Ph.D. level grad students, found that they really want to know about the professors they'll be learning from, so when visiting university websites, these users (and their parents) scrutinized the faculty pages.
Extensive user research with people shopping online identified 5 main types of behavior: product-focused, browsing, researchers, bargain-hunters, and one-time shoppers. Each user type benefits from different UX elements.
To get useful and valid results from a usability study requires a skilled facilitator who avoids biasing the test while ensuring that the users are comfortable. And who can interpret the participants' actions and statements correctly.
To learn something useful from a usability study, you must have the test participants perform tasks that are representative of typical user goals, while avoiding bias caused by giving too detailed directions or hints.