Usability testing
Usability testing is about observing how people actually use a product, by assigning key tasks to users and analyzing their performance and experience.
Why?
When it comes to evaluating the usability of an interface, user testing is often considered unnecessary if an expert has already reviewed it. Since people rarely behave the way you expect, an expert can find major usability problems, but usability tests always reveal surprising issues.
Usability testing and expert reviews are both useful and tend to have different findings, therefore it’s usually recommended to combine the two in order to get the most comprehensive analysis of the interface.
When I hear that teams are not doing usability testing, I wonder what they’re basing design decisions on. When I ask, I often get a mix of answers from, “The CEO wants…” to “market research tells us,” to “we brainstormed in a team meeting.” It feels to me like they’re guessing.