Usability is not user experience, and testing is what keeps it objective. Here is what usability is, how to test it, and the principles behind good design.
Usability is the measure of how effectively, efficiently and satisfyingly a person can use a tool or object, real or virtual. It is one discipline within user experience, not a synonym for it. Usability testing is evaluating a design with real users to keep decisions objective instead of subjective. It matters most at the prototype stage and can be moderated or unmoderated, remote or local, explorative or comparative.
Key takeaways
- Usability is a discipline of UX, not UX itself. It measures ease of use and learnability.
- Without objective user testing, design decisions become subjective, which UX designers must avoid.
- Testing types combine three axes: moderated/unmoderated, remote/local, explorative/comparative.
- Common methods: SUS, lab and guerrilla testing, heatmaps, eye tracking, interviews.
- Dieter Rams' 10 principles of good design still underpin usable, well-crafted products.
What is usability?
Usability is the measure of how effectively a user can utilize a tool or object, whether real or virtual.
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In software terms, usability is the degree to which an application lets specified users achieve goals with effectiveness, efficiency and satisfaction in a given context. It is a component of user experience, not the whole of it.
What about usability testing?
Usability testing is the core of usability: without objective testing, everything is subjective. You can test at every stage of the process (ideation, wireframes, mockups, prototypes), but it becomes essential at the prototype stage, and nothing replaces testing with real users.
Types of user testing
Testing combines three axes that can be mixed: moderated or unmoderated, remote or local, explorative or comparative.
- Moderated: a researcher guides participants through tasks and gathers qualitative feedback.
- Unmoderated: automated tools (like heatmaps) capture behavior without a researcher present.
- Remote vs local: researcher and user apart (video, tools) or together (lab, home, public place).
- Explorative: open-ended, useful for information architecture via card sorting.
- Comparative: users compare options for qualitative preference, unlike A/B testing which is quantitative.
Usability testing methods
- System Usability Scale (SUS)
- Lab testing
- Guerrilla testing
- Hallway testing
- Heatmap analysis
- Eye tracking
- User observation (remote or local)
- Interviews
- Software usage analysis
Dieter Rams' 10 principles of good design
- Good design is innovative.
- Good design makes a product useful.
- Good design is aesthetic.
- Good design makes a product understandable.
- Good design is honest.
- Good design is unobtrusive.
- Good design is long-lasting.
- Good design is thorough down to the last detail.
- Good design is environmentally friendly.
- Good design is as little design as possible.
Usability by the numbers
The measure of how effectively, efficiently and satisfyingly a user can use a tool or object. It is one discipline within user experience.
Evaluating a design with real users to keep decisions objective. It is most essential at the prototype stage.
No. Usability is one part of UX, focused on ease of use and learnability. UX is the whole relationship between a person and a product.
They combine three axes: moderated or unmoderated, remote or local, and explorative or comparative.
Comparative testing gathers qualitative preferences between options; A/B testing measures which version performs better on quantitative metrics.
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