Skip to content
Usability Testing vs. UAT
5 min read

Usability Testing vs UAT

What is User Acceptance Testing?

User Acceptance Testing (UAT) is a phase of software development in which the software is tested out in the real world by the intended audience. In UAT, users have the opportunity to interact with the software to ensure the software is working as intended and identify bugs before it is in production.

UAT is often done by potential end users where they complete a series of test scenarios. End users are the most effective group to test software because they know exactly how the software will be used daily and what changes need to be made to ensure the software is suitable for use. The results from the testers are then forwarded to the developers to make final changes based off feedback. UAT is done to improve product quality and ensure a successful “Go Live”.

User acceptance testing validates that testing was completed at the end of the development cycle. It is completed after unit testing, quality assurance, system testing and integration testing. Practices of user acceptance testing include the following:

  1. Gather information. The correct data must be collected, including the process being tested, the actions that must be taken for tests and a set of guidelines for selecting test data.
  2. Properly identify the target audience. This helps identify UAT users who know what to look for and how to provide useful feedback.
  3. Understand the project scope. Specific processes may not need to be tested, so data can be collected from only the processes needed.
  4. Different testing steps can be assigned to different users. Test cases should also be detailed and specify procedures, expected results and conditions a tester may need to verify.
  5. Confirm business objectives. Once the testing is done and bugs are resolved, a sign-off confirmation should be in place to indicate that changes meet business requirements.

    UAT has the overall goal of testing for final errors in the product. Once a product has gone through the UAT cycle, it should be error-free and ready to go.


    What is Usability Testing?

    Usability testing is a key component in launching a great digital product and focuses on the overall experience of the user and how the product or website makes the user feel. It’s about detecting usability issues with the aim of improving the overall user experience. This is done by monitoring how representative users interact with the product in a realistic setting.

    Testing is important for creating an optimal user experience and should be done early and often during the design process. The UX testing process consists of collecting information about usability and the overall user experience from actual users during the design process. This is done through a variety of user testing methods, including surveys, interviews, and observation of tasks. When conducting a design testing session, you should have several realistic tasks in mind and test all participants on the same task so that you can compare them.

    When observing the completion of tasks, the following can be measured as an indicator of usability:

    • Task completion. Can the user complete the task? What’s stopping the user from completing the task?
    • Time for task. How much time does the user need to complete the task? Does the task take too much or too little time to complete?
    • Flow efficiency. Can users easily navigate through the product? Was any part of the user flow confusing?
    • Error detection. Did users experience any errors? When did the errors occur? Were they avoidable or unavoidable?

    When recruiting users to sit through user testing, it is essential to have established clear selection criteria. Around 3–5 users are enough to identify key issues. The purpose of user testing isn’t to direct users towards the finish line, but to give them enough information to complete the journey intuitively — on their own accord. We recommend having a note-taker during the session to capture participant thoughts.

Differences Between User Acceptance Testing and Usability Testing?

Usability Testing in the Design Thinking Process


UAT represents the final round of testing, while usability testing represents the first. Both tests are important in understanding your design and how effectively it works.

In UAT, unit tests are created to ensure that software will perform as expected. Quality engineers create a test plan to ensure that both automated and manual tests validate as much of the code in as many scenarios as possible. UAT represents the last quality check before the design is released. UAT is a final check to ensure that the product works as designed in the environment where it will be used. The testing feedback comes from real users.

UAT can uncover issues such as:

  • unexpected behavior in particular browser/device configurations that the product team did not evaluate;
  • tweaks needed to make the software integrate better into business operations;
  • copy changes necessary to reflect updated processes.

With user testing, usability experts share sample prototypes of the design with users while it is still early in development. Usability testers will spend time observing users and will ask more questions than they would in UAT. Usability testing can be repeated throughout development. The tasks that take place throughout usability testing are more performance based, judging how well an end user can complete a task within a certain environment provided. The tasks that take place throughout UAT are more so evaluating the success of the system that has been built rather than the user’s success. If usability testing is done early and often, UAT will go much more smoothly and consist mostly of performance tweaks rather than large changes.

UAT deals with functionality and shows us that there was an error, while usability testing deals with user behavior and shows us what the true error was. Overall, both UAT and usability testing will be conducted when developing a product, but usability testing will come first and may be repeated prior to UAT taking place. Both are required for usable products!


Usability testing is one part of the larger design thinking process. To learn more, you might like our Ultimate Guide to Design Thinking