Usability refers to the ease of use and learnability of something.

Within the context of a web site, user interaction should have a perceivable efficiency or elegance.

What is usability?

Usability is a measurable attribute of quality. Industry standard heuristic analysis techniques can assess how easy user interfaces are to use.

There are 5 quality components to usability:

  • Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?
  • Efficiency: Once users have learned the design, how quickly can they perform tasks?
  • Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?
  • Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
  • Satisfaction: How pleasant is it to use the design?

There are other quality attributes. Utility (a design’s functionality) is particularly important. Does it do what users need?

It turns out that usability and utility are equally important. If it’s not what you want, being easy doesn’t help at all.

Useful = usability + utility.

Why is usability important?

Simply put, if a website is difficult to use, people leave. They will find a another site or pick up the phone expecting telephone support.

In a time-poor world, people need to find what they’re looking for quickly. If they can’t find it easily, they will simply look elsewhere. Having good quality content goes a long way towards ensuring good usability.

It therefore makes sense for website owners to allocate budget towards usability (and Accessibility) testing.

How can you improve Usability?

The best thing you can do is test with your users.

  • Recruit representative users.
  • Ask them to perform some representative tasks.
  • Observe what they do.

It should be noted that user testing is different from focus groups. Focus groups are great for market research, however to evaluate interaction design, you must watch what people do. Listening to what people say can be misleading.

After you’ve spoken to users, test variations (prototypes) of the design to discover what matches user’s expectations. Do this early in the design process and keep testing along the way.

Website owners should be prepared to make iterative changes to their website over time. It’s unrealistic to expect “version 1” to be the final version.

Further reading

Of course, we’d also like you to contact us to see how we can help.