User Interaction Design and Prototyping

A human-centred design cycle

Interaction design starts with people trying to achieve goals in a context. Learn about those goals, express the problem, explore candidate solutions, prototype the uncertain parts, evaluate them, and iterate. A requested feature is not automatically a validated need. Someone asking for an export button might actually need to share a summary with a supervisor. Investigate that goal before selecting the interface. Keep assumptions visible, because a polished screen can hide an incorrect model of what users need or which constraints shape their work.

References: Carleton Undergraduate Calendar — COMP 2008 · GOV.UK Service Manual — User research

Research questions, observation, and requirements

Choose a method according to the uncertainty. Interviews help reveal motivations and past experiences; observing actual work exposes interruptions and informal workarounds; usability sessions reveal how an interface supports a task. Ask about concrete recent events instead of inviting speculation about what people might do. Separate observed evidence from interpretation. Convert findings into requirements that describe user outcomes and constraints rather than prematurely specifying widgets. Include participants with different abilities and levels of experience, and document who was not represented so that conclusions are not generalized beyond the evidence.

References: Carleton Undergraduate Calendar — COMP 2008 · GOV.UK Service Manual — User research

Generate alternatives before converging

Ideation creates several plausible responses to the same need. Sketch alternatives that differ in workflow, information organization, or interaction style rather than merely changing color. Evaluate candidates against agreed criteria: task effort, clarity, error consequences, accessibility, feasibility, and maintenance. A storyboard shows the interaction in context, including what happens before and after the main screen. A task flow exposes decision points and recovery paths. Preserve discarded options with a short rationale, because new evidence may reveal that an earlier alternative addressed a constraint more effectively.

References: Carleton Undergraduate Calendar — COMP 2008 · GOV.UK Service Manual — User research

Prototype fidelity and a worked task example

Prototype fidelity should match the question. Paper screens can test labels and navigation; an interactive mockup can test sequencing; a coded prototype can examine keyboard focus or latency. Suppose students must reserve a study room. A useful prototype includes choosing a time, discovering no availability, editing the choice, confirming, and canceling. Testing only the successful confirmation screen hides the difficult decisions. Make unsupported functionality clear during a session, and avoid collecting real payment details or private credentials when fabricated data can answer the same design question.

References: Carleton Undergraduate Calendar — COMP 2008 · GOV.UK Service Manual — User research

Usability evaluation and interpreting evidence

Give participants realistic goals without telling them which control to click. Observe completion, mistakes, hesitation, and recovery. Define success before the session and distinguish completion with help from independent completion. Think-aloud comments are useful, but they are not a direct measurement of every cognitive process. A small qualitative study can reveal important problems without estimating their population frequency reliably. Rank issues by impact, recurrence, and confidence. After revising the design, test the changed task again; a plausible fix may create a different obstacle elsewhere.

References: Carleton Undergraduate Calendar — COMP 2008 · GOV.UK Service Manual — User research

Ethics, accessibility, and traceable iteration

Obtain meaningful consent for research and recording, collect only needed data, and protect participant identities. Avoid manipulative choices that make cancellation or refusal unnecessarily difficult. Accessibility affects the structure of the interaction: clear labels, predictable focus, sufficient contrast, appropriate alternatives, and understandable error messages matter throughout the workflow. W3C tutorials are a practical implementation supplement. Record the link from evidence to requirement to design change to evaluation result. This trail makes decisions reviewable and helps a team distinguish a tested improvement from a personal preference.

References: Carleton Undergraduate Calendar — COMP 2008 · GOV.UK Service Manual — User research · W3C WAI — Accessibility tutorials

Practice & worked answers

Original exercises for this guide.

Public notes & references

Course sources establish the scope above. Reference materials support the explanations; linked lecture notes and books remain with their authors.

• Carleton Undergraduate Calendar — COMP 2008 ↗Calendar course scope · 2026–27
• GOV.UK Service Manual — User research ↗Primary reference · Public reference; checked 2026-11-05
• W3C WAI — Accessibility tutorials ↗Primary reference · Public reference; checked 2026-11-05