Usability Testing

Usability testing is the practice of evaluating a product by observing real users as they attempt to complete tasks. It is the most direct way to discover usability problems and validate design decisions. No amount of internal review can replace watching a real user struggle — or succeed — with your product.

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Why Usability Testing Matters

• Reveals real problems — uncovers issues that designers and developers are blind to
• Provides evidence — replaces opinions with observable data
• Saves money — finding and fixing issues before launch is far cheaper than after
• Improves satisfaction — products tested with users consistently receive higher satisfaction scores
• Builds empathy — watching users struggle motivates teams to prioritise fixes

Key Insight: You are not your user. What seems obvious to the team that built the product is often confusing to someone encountering it for the first time.

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Types of Usability Testing

Type	Description	When to Use
Moderated in-person	Facilitator and participant in the same room	Early-stage testing, complex products
Moderated remote	Facilitator and participant connected via video call	Geographically distributed participants
Unmoderated remote	Participant completes tasks independently using a platform	Large sample sizes, quantitative benchmarking
Guerrilla testing	Informal testing with people in public spaces (cafes, libraries)	Quick feedback on simple prototypes
A/B testing	Two variants shown to different user groups	Comparing specific design alternatives
Expert review (heuristic evaluation)	UX experts evaluate against established principles	Quick identification of obvious issues

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Planning a Usability Test

Step 1: Define Objectives

Clearly state what you want to learn:

• "Can users complete the checkout process without assistance?"
• "Do users understand how to filter search results?"
• "Where do users get confused during onboarding?"

Step 2: Recruit Participants

Consideration	Recommendation
Number	5 participants per round (uncovers approximately 85% of issues)
Representation	Match your target user demographics
Screening	Use a screening questionnaire to filter for relevant experience
Incentives	Offer appropriate compensation for time (gift cards, payment)
Diversity	Include participants with varying abilities, ages, and tech proficiency

Step 3: Write Tasks

Tasks should be realistic scenarios, not instructions:

Good Task	Bad Task
"You want to buy a birthday gift for a friend under 30 pounds. Find something suitable."	"Click on Shop, then Gifts, then filter by price."
"You have just signed up. Set up your profile."	"Click the profile icon in the top right."
"Find out what time the Manchester store closes on Saturdays."	"Go to the Store Locator page and look up Manchester."

Step 4: Prepare the Test Environment

• Set up screen recording and audio recording (with consent)
• Prepare the prototype or product to a testable state
• Create a facilitator guide with tasks, follow-up questions, and timing
• Have note-taking sheets ready for observers

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Facilitating a Test Session

Before the Session

• Welcome the participant and explain the purpose
• Emphasise: "We are testing the product, not you. There are no wrong answers."
• Ask the participant to think aloud as they work through tasks
• Get consent for recording

During the Session