Moderated Usability Testing
Moderated usability testing is a research session in which a moderator watches one participant at a time attempt realistic tasks with a prototype or live service while saying aloud what they are thinking. It shows whether people understand what to do, whether they can complete the task and where exactly they get stuck. The procedure described here follows the guidance of the UK Government Digital Service in the GOV.UK Service Manual; the technique itself is general user-research practice.
Facilitation script
- 1
Welcome the participant, explain the purpose and the recording, obtain consent, and say clearly that the service is being tested and they cannot make mistakes.
5 min - 2
Ask a few warm-up questions about the participant's situation and their experience with this kind of service. Use the answers to make the tasks believable for them.
5 min - 3
Explain thinking aloud and let the participant practise on something trivial, such as finding the opening hours on a familiar website.
3 min - 4
Give the tasks one at a time. Observe in silence, note where the participant hesitates or goes wrong, and ask open follow-up questions after each task.
30 min - 5
Ask closing questions about the overall experience and anything the participant expected and did not find. Pass on questions from observers.
5 min - 6
Thank the participant, explain what happens with the findings, ask how the session felt and hand over any agreed incentive.
2 min - 7
Debrief briefly with the note-taker and observers straight after the participant leaves and write down the main observations while they are fresh.
10 min
Tips
Run a pilot session with a colleague to find broken prototype links and tasks that give the answer away.
When a participant asks whether they are doing it right, hand the question back by asking what they would expect to happen.
Get the wider team to watch live, since watching a real person struggle settles design arguments faster than any report.
The GOV.UK guidance advises no more than six one-hour sessions a day with at least 15 minutes between them.
Common pitfalls
Helping or explaining when the participant struggles, which hides the very problem the session is meant to reveal
Writing tasks that use the same words as the interface labels, so participants match words instead of working out what to do
Asking participants what they would like or whether they would use it, and treating the opinions as findings, when the reliable data is what they did
Testing with colleagues or other people who know the service, which makes the design look far easier than it is
Recording sessions without clear consent or storing the recordings carelessly, which breaches participants' privacy and data protection rules
Variations
Remote moderated testing uses a video call with screen sharing and suits participants who cannot travel; check their setup before the session. Sessions can also take place in the participant's home or workplace, where you see their own devices and assistive technology. For early ideas, test paper sketches or a clickable mock-up. If you have no moderator time and simple tasks, unmoderated testing with a recording tool is an alternative, at the cost of follow-up questions.
Where it fits
When to use it
You have a prototype or a built service and need to know whether people can use it without help
The team disagrees about a design decision and observed behaviour can settle it
Analytics show that users drop out at a step and you need to see why
You are starting a redesign and want to evaluate the current service first
You want developers, designers and decision-makers to see real users with the product
When not to use it
You do not yet know what users need or what problem to solve; run user interviews or contextual inquiry first, since a usability test only evaluates what you put in front of people
You want to know whether people would buy or prefer a concept; what they do in a test task says little about demand, so use concept testing or a live experiment
You need statistically reliable numbers such as completion rates across a large population; use analytics or a larger unmoderated study
You cannot recruit real or likely users and would test with colleagues; the findings would reflect insider knowledge
Related methods
Frequently asked questions
What is Moderated Usability Testing?▾
It is a user-research method in which a moderator sits with one participant, in person or remotely, and watches them try to complete realistic tasks with a prototype or service. The participant thinks aloud, and the moderator observes and asks follow-up questions. The aim is to find out where the design causes problems.
How long should a usability test session be?▾
The GOV.UK Service Manual gives 30 to 60 minutes, depending on the number and difficulty of the tasks. It also recommends at most six one-hour sessions in a day, with at least 15 minutes between sessions and a lunch break.
What makes a good usability test task?▾
A good task sets a clear goal, is relevant and believable for the participant, is demanding enough to expose problems and does not give away the answer in its wording. Use several smaller tasks in a sensible order. Describe the situation and let the participant work out where to go.
Who needs to be involved in a session?▾
One participant, one moderator who introduces the tasks and asks questions, and one note-taker. Other team members can observe from a separate room or a video stream. Keep observers out of the participant's sight where possible so the participant does not feel examined.
What is the difference between moderated and unmoderated usability testing?▾
In a moderated test a researcher is present and can probe why something happened or help a participant who is completely stuck move on. In an unmoderated test participants work alone through set tasks with a recording tool. Unmoderated tests are cheaper and faster to run in volume, but you cannot ask follow-up questions.
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Try it freeMethod descriptions on Workshop Weaver are original content written by our team, based on established facilitation practices. This method was inspired by work from GOV.UK Service Manual (UK Government Digital Service).