Usability Testing

What is usability testing?

Usability testing is the process of evaluating a product or service by testing it with users and observing their behavior. These tests can be performed with individuals or in a group and focus on user behavior. Participants will try to complete set tasks while observers watch, listen, and take notes. The results from the test are then used to make improvements to the product.

When should I conduct a usability test?

Usability testing should be done iteratively throughout a project, starting with wireframes or prototypes. Design mockups can also be used for testing.

Why should I perform a usability test?

  1. Usability tests help you identify problems early in the project when they’re much easier to fix.
  2. Collect data.
  3. Determine the participant’s satisfaction with the product.

How to conduct a usability test

Identify your target audience. If you’re testing an existing site, you can leverage analytics to do this. Write a test plan including a script and the interactions/features to be tested, create and prioritize tasks that the user can complete during the test – aim for 5-10 tasks for a 60 minute test. Make the tasks realistic, actionable, and avoid giving clues to the answers. Ideally a usability test should include a facilitator and a note taker. If a note taker is unavailable, the facilitator can take notes but they likely won’t be as thorough.

Facilitator reads a participant one task at a time and allows the participant to complete the task without intervention until all tasks are complete. Be sure to take notes on the questions that are being asked. Ask the participant to talk through their task aloud to better understand their decision-making. Take note of the time it takes a user to complete each task. Take notes on what they say, areas they struggle in, and places where content may be unclear. We recommend testing with 3-5 participants per round of testing. Test one participant per session.

Task Writing Tips:

  • Make the task realistic.
  • Make the task actionable.
  • Avoid giving clues and describing the steps.

Test moderating tips:

  • Don’t lead the participant.
  • Don’t interrupt at the wrong time.
  • Follow a script/checklist to prevent bias.
  • Observe and listen.


Usability testing involves a heavy investment compared to other user research methods. First, you need something to test -- prototypes, wireframes, designs, etc. -- which require effort and research to create themselves. You also need to recruit participants and compensate them in some way. Finally, the results of the test need to be documented in a way that is useful for the design team.


The results from usability testing are nearly irrefutable. When you ask a real user to use a real product and notice a trend that an element of that product is problematic, then that element is almost certainly problematic.


There are many resources available to assist with facilitation of usability testing, and doing it right does require thoughtful pre-work. A key pitfall to be aware of is the potential for a facilitator to prime a participant, which can potentially invalidate results. Usability tests greatly benefit from a skilled hand.