Glossary · 7 · Evaluation methods
Usability testing
Also known as: Usability test, User testing
German: Usability-Test
Usability testing is an evaluation method in which representative users perform realistic tasks with a product, a prototype or its information while observers record whether and how they succeed, the time and effort needed, the errors they make and their satisfaction, in order to assess usability — the effectiveness, efficiency and satisfaction with which specified users achieve specified goals in a specified context of use (ISO 9241-11:2018).
- Applied cognitive psychology
- Evaluation methods
In one sentence
Usability testing observes representative users doing real tasks with a product or its information to measure effectiveness, efficiency and satisfaction.
Example
Five maintenance technicians each perform three tasks with the draft manual of a capper. Two cannot find the torque settings, one skips a lockout step because it is on the previous page; the team moves the lockout step into each task and tests again.
Rests on
- Human information processing: tests reveal where perception, comprehension or action break down.
- Gulfs of execution and evaluation and Slips, lapses and mistakes: observed errors are classified by where they arise, which points to the design fix.
- Curse of knowledge: authors cannot predict readers' problems reliably, so readers are observed.
How it applies
- Testing instructions for use: Representative users perform real tasks with the product and the instructions for use; measure task success, errors, time and satisfaction, and record the problems and the changes made. Small iterative tests with a few users find many problems early.
- Methods: Moderated or unmoderated, in the lab, remote or at the machine; often combined with a think-aloud protocol.
- Medical devices: Usability engineering, including formative and summative evaluation of the user interface with its accompanying documentation, is formalized in IEC 62366-1.
- Human-centred design: ISO 9241-210:2019 places evaluation with users in an iterative design cycle.
Usability testing vs. usability
Usability is the property defined in ISO 9241-11:2018; usability testing is one way to evaluate it. Others are inspections (cognitive walkthrough, heuristic evaluation), surveys and analytics.
Limits
- A test shows problems for the tasks, users and conditions tested; it cannot prove that a document has no problems.
- Tests at real machines must not expose participants to hazards.
- Test results do not establish compliance and do not replace the risk assessment; they show whether the required information is found, understood and applied.