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.