What It Is

Giving real users specific tasks to complete and observing what happens. Where do they get stuck? Where do they hesitate? Where do they give up or take a wrong turn? The interface tells you what it thinks is clear. Users tell you what actually is.

Moderated vs. Unmoderated

Moderated means a researcher is present — they can probe, ask follow-up questions, and explore unexpected behaviors. Better for complex flows and early-stage designs. Unmoderated means participants complete tasks remotely on their own — larger sample sizes, faster turnaround, better for quick validation of specific interactions.

Think-Aloud Protocol

Ask participants to verbalize their thinking as they go. "I'm looking for the settings button... I expected it to be up here... I'm not sure what this icon means." This reveals mental models and expectations that you'd never see from behavior alone.

What It Produces

A prioritized list of usability issues with severity ratings. Video evidence that makes stakeholders feel the pain directly. And specific recommendations tied to interface elements — not abstract principles, but "this button label should say X because participants expected Y."