Usability testing
Observe people attempting meaningful tasks
Usability testing observes intended users attempting representative tasks with an interface or prototype. Formative tests diagnose problems; summative tests estimate performance against defined criteria. Success, errors, time, observations and perceived usability can be combined, but must retain their different meanings. Moderated, remote and unmoderated formats differ in what context and process evidence they reveal.
Choose it when you need to discover interaction obstacles or judge task performance and can recruit relevant users, define realistic tasks and provide a prototype with the required fidelity.
Strengths
- Reveals actual interaction difficulties rather than stated preferences alone
- Combines behavioural evidence with explanations of confusion
Limitations
- Artificial tasks and observation can change behaviour
- Small diagnostic studies cannot precisely estimate population failure rates
Know the boundary
A usability test does not by itself establish market demand, accessibility compliance or improved learning.