Heuristic Evaluation (HE)
What Is Heuristic Evaluation?
Heuristic Evaluation is an analytical, expert-based usability inspection method. Evaluators examine an interface and judge its compliance with a small set of established usability principles (heuristics). It requires no users, no working system, and relatively little time — making it one of the most cost-effective evaluation methods.
Best practice: use 3–5 independent evaluators. Nielsen’s research shows a single evaluator finds only ~35% of usability problems; 3–5 evaluators find the large majority at reasonable cost. Evaluators must work independently before their findings are aggregated, to avoid groupthink.
Nielsen’s 10 Heuristics — Full Reference
| # | Heuristic | What to look for |
|---|---|---|
| 1 | Visibility of System Status | Keep users informed via timely, appropriate feedback. Loading indicators, progress bars, confirmations. Violation: no feedback after clicking a button — the user does not know if the action was received. |
| 2 | Match Between System and the Real World | Speak the user’s language, not internal jargon. Follow real-world conventions. Violation: raw technical error codes shown to non-technical end users. |
| 3 | User Control and Freedom | Support undo/redo. Provide clearly marked “emergency exits” — users need a way out. Violation: no way to undo an irreversible “delete all” action. |
| 4 | Consistency and Standards | Follow platform conventions (iOS HIG, Material Design). Be internally consistent — the same action should look and behave the same way everywhere. Violation: the same function labelled differently on different screens. |
| 5 | Error Prevention | Design to prevent problems before they occur. Confirmation dialogues for destructive actions, input validation, disabling invalid options. Better than a good error message. Violation: no confirmation before an irreversible deletion. |
| 6 | Recognition Rather Than Recall | Minimise memory load by making objects, actions, and options visible. Violation: requiring users to remember commands with no visible hints (echoes the Memory lecture). |
| 7 | Flexibility and Efficiency of Use | Provide accelerators (shortcuts, gestures) for expert users, invisible to novices. Allow customisation. Violation: all users must navigate full menus for every action — no shortcuts exist. |
| 8 | Aesthetic and Minimalist Design | Dialogues should not contain irrelevant or rarely-needed information. Every extra element competes for attention. Violation: an overwhelming first-run screen with too many simultaneous options. |
| 9 | Help Users Recognise, Diagnose, and Recover from Errors | Plain-language error messages that precisely state the problem and suggest a solution. Violation: “Error 404” with no explanation or next step. |
| 10 | Help and Documentation | Even though the ideal system needs no explanation, provide easily searchable, task-focused help. Violation: no help section, or one hidden several clicks deep. |
HE Procedure
- Brief evaluators on the 10 heuristics and the intended context of use / user population. Evaluators do not need to be the designers.
- Each evaluator inspects independently — no discussion during evaluation.
- For each problem found, record: which heuristic(s) are violated, precisely where the violation occurs in the interface, and a severity rating (0–4).
- Aggregate findings across evaluators; merge duplicates.
- Prioritise for redesign by severity × frequency. A severity-4 problem affecting a core user journey takes priority over a severity-2 cosmetic issue on a rarely-visited settings page.
Severity Rating Scale (0–4)
| Rating | Meaning |
|---|---|
| 0 | Not a usability problem at all. |
| 1 | Cosmetic only — fix if time allows. |
| 2 | Minor usability problem — low priority. |
| 3 | Major usability problem — important to fix. |
| 4 | Usability catastrophe — must fix before release. |
Severity combines frequency (how often is it encountered?), impact (how hard is it to overcome?), and persistence (one-time annoyance or recurring obstacle?).
Worked Example: HE of Microsoft Teams (2025 Q6a)
| Problem | Heuristic Violated & Reasoning |
|---|---|
| Buffering/long loading on brief internet interruption | #1 Visibility of System Status — no clear feedback about connection state or load progress |
| No demonstration of common tasks for new users | #10 Help and Documentation — novices are left unsupported with no onboarding |
| No wizard guiding users starting an activity | #6 Recognition Rather Than Recall — users must remember how to start, with nothing visible to prompt them |
| Layout not ordered to match task steps | #2 Match Between System and Real World — on-screen order does not mirror the real workflow |
| Untrained users struggle with numerous/complex features | #7 Flexibility and Efficiency of Use — caters to experts with no progressive disclosure for novices |
| No advanced search feature | #7 — experts lack a shortcut to precise retrieval; all users must browse |
| New posts overwrite/bury important files & assignments | #8 Aesthetic and Minimalist Design (also #1) — important information lacks visual hierarchy |
| Left-hand navigation hard to reach on mobile | #2 / platform conventions — mobile convention favours bottom/thumb-zone navigation; a desktop pattern was ported unchanged |
Should You Combine Heuristics?
A known debate: fewer heuristics are faster to learn and apply, speeding up evaluation. However, combining conceptually distinct heuristics risks missing subtle issues — e.g. merging #1 (Visibility) and #9 (Error Recovery) under “feedback” might cause evaluators to overlook visibility problems that are not framed as errors. The trade-off is completeness vs practicality: for a quick sanity check, a reduced set may suffice; for a formal, reproducible audit, the full 10 should be retained.
Expected Learning
- Name all 10 of Nielsen’s heuristics with a one-sentence description of each.
- Given an interface description or screenshot, identify specific violations, naming the heuristic, the location, and the reasoning.
- Apply a severity rating (0–4) to each violation and justify the rating.
- Explain why evaluators must work independently and why 3–5 evaluators is the empirically-supported sweet spot.
- Discuss the trade-off of combining heuristics (completeness vs speed/practicality).
Past Paper Questions
HE appears in almost every Tripos sitting: 2025 Q6a (Teams), 2024 Q5 (ChatGPT), 2021 Q5, 2020 Q5d, 2019 Q5, 2018 Q5, 2017 Q6c. HE is the single most frequently examined topic on the paper — be fluent with all 10 heuristics and the procedure.