Usability · A Practitioner's Guide

What is usability, and why does it matter?

Usability is the quality that makes a product easy, efficient, and satisfying to use. It is not one thing — it is a composite of learnability, efficiency, memorability, error tolerance, and satisfaction. Get it right and people accomplish their goals. Get it wrong and they leave, or make costly mistakes.

Recruiting Participants

The problem with “The General Public”

Research aimed at “anyone” produces findings that apply to no one. Every product has a real user — a person with domain knowledge, a mental model shaped by prior tools, and specific goals. Recruiting outside that population generates noise, not signal. You end up optimising for a fictional user while your actual users suffer.

Screener designParticipant profilesPanel recruitmentInternal recruiting

How to recruit the right people

1Define your user profile first. Role, domain knowledge, frequency of use, technical comfort — be specific before opening any recruiting tool.
2Write a tight screener. 6–8 questions max. Avoid leading language. Screen on behaviours, not demographics alone.
3Use multiple channels. Customer success teams, LinkedIn, existing panels, UX agencies. Do not rely on a single source.
4Plan for 5–8 participants per segment. Diminishing returns kick in fast; beyond 8 you are confirming, not discovering.
5Compensate fairly. Poor incentives bias your sample toward people who need the money, not your target user.
Takeaway: Specificity in recruiting is the difference between research that changes product decisions and research that validates whatever stakeholders already believed.
Basics of User Experience

The five components of usability

1Learnability — How quickly can a new user accomplish basic tasks on first encounter?
2Efficiency — Once learned, how fast can experienced users reach their goals?
3Memorability — When users return after an absence, can they re-establish proficiency quickly?
4Error tolerance — How severe are mistakes, and how easily can users recover?
5Satisfaction — Is the experience pleasant and fulfilling to use?

UX is not UI

UI is the surface — buttons, typography, colour. UX is the entire experience a person has: the first moment of confusion, the moment of success, the feeling after the session ends. A polished UI on top of a broken information architecture is still a bad experience.

Information ArchitectureInteraction DesignVisual DesignContent Strategy
Takeaway: Usability is a quality attribute, not a deliverable. You cannot hand someone “usability” — you can only measure and improve it through observation.
Methods

Choosing the right method

No single method answers every question. The choice depends on where you are in the design process and what you need to know.

QQualitative — moderated testing, contextual inquiry, cognitive walkthroughs. Use when you need to understand why.
QQuantitative — unmoderated testing, surveys, analytics. Use when you need to measure how many and how often.
AAttitudinal vs. behavioural. What people say and what they do are often different. Prefer behavioural data when available.

Method reference

→Card sorting — reveals mental models for navigation. Run early.
→Tree testing — validates IA without visual design interference. Run after card sorting.
→Diary studies — captures longitudinal experience over days or weeks. Costly but uniquely revealing.
→Heuristic evaluation — fast expert review. Surfaces obvious issues before participant studies.
→First-click testing — validates whether users find the right starting point for a task.
Takeaway: Mix generative and evaluative methods. Generative tells you what to build; evaluative tells you whether you built it well.
Guidelines

Nielsen's 10 heuristics

1Visibility of system status — always keep users informed about what is happening.
2Match the real world — use words and concepts the user knows.
3User control & freedom — support undo, redo, and easy exits.
4Consistency & standards — follow platform conventions.
5Error prevention — design to prevent problems first.
6Recognition over recall — make options visible; do not make users memorise.
7Flexibility & efficiency — accelerators for experts; do not punish novices.
8Aesthetic & minimalist design — every extra element competes for attention.
9Help users recognise & recover from errors — plain language, precise, constructive.
10Help & documentation — easy to find, action-oriented.
Takeaway: Heuristics are a diagnostic vocabulary, not a design spec. Severity is context-dependent — a violation affecting 80% of users daily dwarfs one affecting 0.1% weekly.

How To & Tools

Practical frameworks and approaches

Select a topic to explore a structured breakdown — from running research to managing projects and designing for clarity.

Content Strategy in UX

Content is the product. Words, labels, instructions, and error messages are interface elements — not filler. Content strategy in UX means designing the information architecture, hierarchy, and language from the first wireframe.

Voice & ToneMicrocopyPlain LanguageIA

Core principles

1Lead with the user's goal. Labels, headings, and CTAs should answer “what does the user want to do?” not “what does this section contain?”
2Write at the level of your audience. Plain language reduces cognitive load for everyone. Jargon is acceptable when the audience genuinely owns it.
3Error messages are content. “Something went wrong” is not a message. Tell users what happened, what it means, and how to fix it.
4Audit before redesign. Inventory what exists, what's redundant, what's missing before redesigning anything.
5Test your labels. Card sorting and first-click tests validate whether labels are interpreted as intended.
Takeaway: “We'll fix the copy later” is how products ship with confirmation dialogs saying “Are you sure?” and errors saying “Error 403.” Make content a first-class design decision.

Managing UX Research Projects

UX research does not manage itself. Without a clear plan, studies run over schedule, findings get buried in decks nobody reads, and stakeholders lose confidence in the process. Treat research like a product: scope it, schedule it, ship findings on time.

Research OpsStakeholder MgmtPlanning

A lightweight UX project framework

1Research brief (day 1). Document the research question, not the solution hypothesis. Align stakeholders before recruiting starts.
2Study plan (week 1). Method, participant criteria, screener, session guide, schedule, roles. Written, reviewed, approved.
3Pilot session. Run one session with a colleague first. Catch broken prototypes and timing issues.
4Same-day synthesis. Cluster observations within 24 hours. Do not batch synthesis to the end of a two-week study.
5Two-format readout. A one-page summary for quick decisions. A detailed report for the record. Lead with the one-pager.
6Track decisions, not just findings. What changed because of this research? Document it. This is how research builds credibility over time.
Takeaway: A 3-day study with clear output beats a 3-week study with a 60-slide deck nobody finishes reading. Research velocity matters.

Visual Design as a Usability Tool

Visual design is not decoration — it is communication. Every spacing decision, contrast ratio, and typographic weight is either helping users understand a hierarchy or making it harder. Ask of every visual decision: does this help users know what to do next?

Visual HierarchyColour & ContrastTypographySpacing

Principles that drive usability through visual design

1Hierarchy before aesthetics. Define primary, secondary, and tertiary actions before choosing colours. The most important action should be most visually prominent.
2WCAG AA as a floor. 4.5:1 contrast ratio for text is the minimum. Aim for 7:1 in data-dense contexts.
3Do not communicate with colour alone. 8% of males have some form of colour blindness. Use shape, label, and pattern alongside colour.
4Whitespace is information architecture. Spacing groups related elements and separates unrelated ones. Insufficient whitespace makes everything feel equally important.
5Typography is UI. Font size, weight, and line-height determine whether users can scan efficiently. 16px body, 1.5 line-height, limited weight range.
Takeaway: A usability test revealing users ignoring your primary CTA is often a visual design problem. Hierarchy, contrast, and size communicate intent before the user reads a single word.
homePortfolio lightbulbTechnical Insights buildTools & Experiments