What is a usability test?

Usability testing refers to the evaluation of a product or service by testing it with representative users. It usually involves observing people as they try to complete tasks given by the test moderator.

Usability studies allow us to collect qualitative behavioural data, as well as learn behaviours and cognitive patterns.

The importance of testing

We can’t predict exactly how people will respond to an interface without first testing it. Usability testing allows design and development teams to identify the most significant problems.

The sooner problems are identified and corrected, the less it costs, the better the experience and the less impact it has on development time.

Planning - What you’ll need

• Define objectives and start a research plan

• Determine the format and orientation of the study

• Determine and recruit participants

• Write the test tasks

• Conduct a first pilot test

• Decide on metrics and success criteria

• Motivate others in the team to observe

Determine what you want to learn, identify the questions, concerns and purpose of the research.

Example: Is it easy for users to find the library timetable?

Don’t commit to too many objectives in one study.

Determine the study format

The tests can be carried out in a laboratory or in a context. As well as choosing the location, you’ll need to set a time for each participant and have an organised schedule.

Moderate or not moderate

Moderated tests tend to provide more valuable insights and opportunities due to their nature. They can also be completed by asking or recalling the think aloud protocol.

In person or remotely

Generally, whenever possible, studies should be carried out in person, as it’s possible to analyse more data, particularly body language. However, with remote opportunities, we often choose to test remotely using tools such as Zoom, Lookback, etc.

Determine the number of users

According to Jakob Nielsen, 5 users should be enough for a usability test. Not to be confused with contextual interviews where this number is different.

On average, 5 users discover 75% of the most serious usability problems. It’s better to do several studies with 5 people than just one study with 20 participants.

Don’t forget to recruit one or two extra people to account for those who might be missing.

Recruiting the right participants

The best insights come from obtaining feedback from real users. That’s why it’s preferable to recruit the most representative users we can.

Write tasks according to the test objectives

In a usability test, people are asked to complete a series of activities while using an interface, product or service. These activities or tasks are usually written within scenarios and fulfil the objectives of the study.

Writing contextual and realistic tasks is essential for carrying out a valid usability test.

Use exploratory tasks to learn more about behaviour

Exploratory tasks allow you to learn how people discover or explore information.

Example: You’re interested in booking a holiday for your family. See if you can find what fulfils your needs.

In more quantitative tests or to validate flows, more specific written tasks can be used, but without ever referring to parts of the interface or information that could create cognitive biases in the participant.

✅ Good example: Find the opening hours of the municipal library.

❌ Bad example: Find the contact page.

Decide to collect metrics

The time it takes to complete the task, degree of satisfaction, success or error rate, and recommendations are some of the most common metrics to be used in usability testing.

Do a pilot test

Pilot testing helps you fine-tune the details of certain tasks or your script. It also helps you validate that you’ll be testing with the right audience.

These pilot tests can be even more critical when it comes to unmoderated remote tests.

Let’s test!

We’re ready to start testing and validating our path. 😎

And don’t forget to bring a member of your team or the customer themselves, if that’s the case. There’s nothing more valuable than seeing real users using our product. It’s the easiest way to convince someone that the right changes need to be made!