Usability Testing
Observing users attempting tasks to identify interface problems.
Definition
Usability Testing involves observing real users attempting to complete tasks with a product to identify usability problems, understand behaviors, and gather qualitative feedback. Tests can be moderated (with a facilitator) or unmoderated (self-guided) and conducted in-person or remotely.
Testing reveals where users get confused, what features they miss, where flows break down, and how actual behavior differs from designer assumptions. Even testing with 5 users typically uncovers 80%+ of major usability issues.
Why It Matters
Usability testing prevents launching products with fundamental usability problems that frustrate users and reduce conversion. Issues obvious during testing often surprise designers, revealing gaps between intended and actual user behavior.
Regular usability testing throughout design and development catches issues early when they're cheapest to fix. Post-launch testing identifies opportunities for optimization and explains unexpected metrics.
Examples in Practice
Testing an e-commerce checkout might reveal users abandoning at the shipping step because they can't find where to enter a promo code. Testing a navigation redesign might show users unable to find previously accessible features.
Moderated tests allow facilitators to ask "What are you thinking?" as users work, revealing confusion even when users complete tasks successfully. Unmoderated tests show behavior at scale but miss deeper insights about why users struggle.