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Usability Testing: Home

So, you have a new web site or piece of software. To make it most useful, you need to have some users actually test it. This LibGuide lists some resources for conducting usability tests.


Welcome to the Usability Testing Library Guide. Here we will cover some of the best practices in conducting a usability test, helpful tips for making your test successful, and compare and contrast some of the most common software used for usability testing.

What is Usability?

From Nielsen: 

Usability is a quality attribute that assesses how easy user interfaces are to use. The word "usability" also refers to methods for improving ease-of-use during the design process.

Usability is defined by 5 quality components:

  • 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 many other important quality attributes. A key one is utility, which refers to the design's functionality: Does it do what users need?

Usability and utility are equally important and together determine whether something is useful: It matters little that something is easy if it's not what you want. It's also no good if the system can hypothetically do what you want, but you can't make it happen because the user interface is too difficult. To study a design's utility, you can use the same user research methods that improve usability.

  • Definition of Utility = whether it provides the features you need.
  • Definition of Usability = how easy & pleasant these features are to use.
  • Definition of Useful = usability + utility.

In short, usability is the ease with which someone interacts with a user interface. This can be applied to physical interfaces, like ATMs, or digital interfaces, which are the focus of this Library Guide.

What is Usability/User Testing?

Again, Nielsen provides a good definition of this subject:

There are many methods for studying usability, but the most basic and useful is user testing, which has 3 components:

  • Get hold of some representative users, such as customers for an ecommerce site or employees for an intranet (in the latter case, they should work outside your department).
  • Ask the users to perform representative tasks with the design.
  • Observe what the users do, where they succeed, and where they have difficulties with the user interface. Shut up and let the users do the talking.

It's important to test users individually and let them solve any problems on their own. If you help them or direct their attention to any particular part of the screen, you have contaminated the test results.

To identify a design's most important usability problems, testing 5 users is typically enough. Rather than run a big, expensive study, it's a better use of resources to run many small tests and revise the design between each one so you can fix the usability flaws as you identify them. Iterative design is the best way to increase the quality of user experience. The more versions and interface ideas you test with users, the better.

User testing is different from focus groups, which are a poor way of evaluating design usability. Focus groups have a place in market research, but to evaluate interaction designs you must closely observe individual users as they perform tasks with the user interface. Listening to what people say is misleading: you have to watch what they actually do.

Using this definition as a foundation for our understanding of user testing, this Library Guide will provide two resources to help you conduct successful user tests. The first resource is a list of best practices for user studies, and the second is a comparison of user testing software commonly used in usability research.

You can also find our software-specific Library Guides in the "Usability Testing Software" tab. 

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