What is Usability?
Usability is a quality attribute that assesses how easily a person can navigate and interact with a user interface. It also refers to the specific methodologies used to improve ease-of-use during the design and development process.
The Five Pillars of Usability:
- Learnability: How easily can users accomplish basic tasks the first time they encounter the design?
- Efficiency: Once users are familiar with the design, how quickly can they perform tasks?
- Memorability: When users return after a period of absence, how easily can they regain proficiency?
- Errors: How many errors do users make, how severe are they, and how easily can they recover?
- Satisfaction: How pleasant is it to interact with the design?
Why Usability Matters
The rule of the web is simple: if a website is difficult to use, people leave. If the navigation is unclear or the content is hard to read, users will seek information elsewhere.
Practical User Testing
The most effective way to measure usability is through direct user testing. Unlike focus groups, which prioritize opinions, user testing focuses on behavior.
The Five-User Protocol:
- Recruit: Find five users who represent your primary target audience.
- Assign Tasks: Ask them to perform three specific tasks (e.g., "Find the undergraduate application" or "Locate orientation registration").
- Observe: Watch where they succeed and where they struggle.
- Listen: Encourage users to "think out loud" so you can record their thought processes.
- Do Not Intervene: It is critical that you do not help the user. Let them problem-solve independently to see where the interface fails.