Usability testing vs user acceptance testing: what’s the difference?


Trent Nguyen

Imagine you spent hours lovingly shopping for, cooking and presenting a delicious meal — only to discover that your guest was allergic to its ingredients.

That is the cooking equivalent of a world without usability testing.  It’s not a world you want to live in.

Sometimes during project scoping and planning at Nexient, we run into confusion about the difference between usability and user acceptance testing (UAT).

It’s easy to understand the confusion: at a basic level, both involve getting feedback from real users to create a better product. But they happen at opposite stages of development and involve very different methodologies and objectives.

Here’s a double-click:

UAT: The FINAL test

Software quality is an iterative process.  Developers create unit tests to ensure that software will perform as expected even before they write a line of code. 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 very last mile of quality before release. It’s a final check to ensure that the product works as designed, in the environment where it will really be used.  The testing feedback comes from real users, and not just members of the product team.

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.
UAT exists to answer the question: will this work as we expected it to?

Usability testing: The FIRST test

If UAT represents the last mile of quality, you can think of usability testing as the first — at least as far as user experience is concerned.  

Usability analysts typically share sample pages or screens with users early in development— often before coding starts, when it’s infinitely less expensive to make changes. Analysts will spend a lot of time observing, and ask many more questions than in UAT. It’s advisable to repeat usability testing throughout development.

Usability testing helps uncover issues such as:

  • wording, imagery or iconography that confuses (or even offends!);
  • process bottlenecks that frustrate users and lead to abandonment;
  • a mismatch between user expectations and product design.
Usability testing exists to answer the question: are we building the right thing, in a way that’s pleasing and intuitive for the user?

What you can expect to learn from usability testing

UX teams use a combination of observation and questioning to understand how users:

  • Interact with your product (where they look, what they consider)
  • Accomplish particular tasks (often, not as you intended, and sometimes not at all!)
  • Expect your software to work
  • Search for information
  • Interpret the words on a button or menu
  • Feel about the colors or images of your product
  • React to potential new features or designs
  • Like using your software
  • Get stuck or bogged down

When should you do usability testing?

At Nexient, we recommend incorporating usability into a project’s sprint cycle, allowing real users to interact with early concepts, while the rest of the team focuses on other areas of development. The agile development process allows the team to iterate on a design, and to incorporate their findings into the product backlog for development in future sprints.

Insufficient usability testing (or usability testing conducted too late in the process) runs the risk of developing a functionally excellent product that people don’t want to or cannot use. It means spending a lot of time and money developing a solution before you truly understand the problem.

Together usability and user acceptance testing pair well, ensuring that your product is appetizing for all.

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