DEV Community

Cover image for User Testing, An Introduction
Christian Baverstock for OneAdvanced

Posted on

User Testing, An Introduction

This blog was originally written by former Advanced Senior UX Designer Cormac Maher and posted to Advanced's design system website, full credit and thanks to Cormac!

What is User Testing

User testing is the process by which we test the interface and functionality of a digital product, using various methods and metrics.

The main goal of user testing is to identify any usability problems in our product’s user friendliness, efficiency, accessibility, and learnability.

Uncovering these issues enables us to determine satisfaction with our product, and allows us to improve the overall user experience before the product’s development and release.

In user testing there are two types of research and data - quantitative and qualitative. Quantitative research is designed to gather data in measurable, numerical form. Qualitative research is data gathered from observation and feedback, and the collection of insights such as opinions, actions and motivations.

How we Perform User Tests

During most user testing sessions, a researcher, also known as the facilitator or mediator, asks a test participant to perform tasks on the product being tested.

While the participant completes each task, the researcher observes the participant’s on-screen actions, their body language, and listens to their think aloud feedback .

At the end of a session the researcher may ask followup questions in a debriefing session to elicit further detail from the participant.

User testing sessions can be carried out either in person, where the facilitator and test subject are in the same room, or remotely, by telephone or over the internet.

When to use User Testing

User testing should be carried out at every stage of the development of our product, and it should be considered an integral part of an iterative design process.

Testing rapidly and repeatedly allows us gather early feedback on our products. This feedback helps identify and correct major design issues before the production stages of the development process, when addressing them will be more difficult and expensive.

In the discovery phase of the design process, before prototype design begins, valuable insights can be gained from analytics and user surveys. While neither of these are strictly considered user testing, we can use these methods to gain valuable insight into user behaviour, and channel that data back into actionable design artifacts.

Card sorting, using OptimalSort - retrieved from
Other user testing methods we can use at this early stage include tree testing and card sorting, these two methods allow us to categorise content, and define our product’s menu structure.

With all of this information we can identify core functionality, key tasks and design our information architecture, navigation, and visual hierarchy accordingly.

After the discovery phase, and in the early stages of prototype design, testing can be performed using lo-fi paper prototypes. These prototypes can be drawn by hand, on a sheet of paper, or created on a computer, and printed. The low fidelity nature of these prototypes means the design can be easily adjusted and evolve rapidly, based on feedback, with little effort or expense.

Later, during the digital prototyping phase, we can use low or high fidelity prototypes, with more functionality and clickable, interactive elements to gauge the ability of participants to complete tasks.

Using these more evolved prototypes, we can start to measure more complex tasks, with increased accuracy. Useful metrics include task completion rate, and task completion time.

A/B testing, retrieved from
After the development of our product, we can continue to perform user testing - refining and optimising our product further. Amongst the many testing methods we can use post-development, are contextual inquiry, where we observe our product in their place of use, with real users, A/B testing where we test different versions of our designs, measuring the difference in performance, and the on-screen behaviour of users can be analysed using heatmaps, scroll maps or analytics.

Website heatmap retrieved from

How Many Participants are Needed

Qualitative research is usually the best starting point to quickly identify problems, and get ideas for how to improve our designs. For a typical qualitative usability study of a single user group, five participants are recommended to test each iteration of a design. If a product has multiple distinct user groups, the number of test groups will need to increase accordingly.

Why You Only Need to Test with 5 Users - retrieved from
Quantitative usability testing focuses on collecting measurable data, which can be used to describe the user experience. With quantitative studies, researchers look for patterns within the collected data, so the more participants we have, the more accurate our data will be. For this study type, at least 20 participants are required, and often more - depending on the complexity of the product and the numbers of tasks, flows, and features.


User testing is a great way to get to know our users. We learn who they are, what they want and why they need our product. Testing allows us to refine our designs efficiently and cost-effectively, and to produce something that will enhance our users day to day lives. It will reduce support requests, improve our NPS score, save money and can give us an easily-achievable edge over our competitors.

This blog was originally written by former Advanced Senior UX Designer Cormac Maher and posted to Advanced's design system website, full credit and thanks to Cormac!

Top comments (0)