Heuristics and Usability Testing

Introduction

How do you know if a design works? Two complementary approaches are expert review with heuristics and usability testing with real people. Together they find many problems before a product launches.

The ten usability heuristics

Jakob Nielsen's heuristics are widely used rules of thumb for interface design:

1. Visibility of system status: keep users informed, such as a progress bar.
2. Match between system and the real world: use words and ideas users know.
3. User control and freedom: provide undo, cancel and a clear exit.
4. Consistency and standards: same things look and work the same way.
5. Error prevention: design so mistakes are less likely, for example confirm destructive actions.
6. Recognition rather than recall: show options instead of making people remember.
7. Flexibility and efficiency of use: shortcuts for experts, simple paths for beginners.
8. Aesthetic and minimalist design: remove irrelevant information.
9. Help users recognise, diagnose and recover from errors: plain-language messages that suggest a fix.
10. Help and documentation: easy to find, focused on tasks.

Heuristic evaluation

To review a design:

1. Choose a task and walk through it screen by screen.
2. At each step, check the ten heuristics, and note problems with the screen, the heuristic and a severity.
3. Ideally, have several reviewers work separately, then combine. Different people find different issues.

Heuristic review is fast and cheap, but it is opinion, not proof of what real users do. Use it alongside testing.

Usability testing

A usability test means watching real people try to do real tasks with your product or prototype.

Plan:

• Goals: what do you want to learn?
• Participants: people like your real users. Five per round is a common, practical number for finding the main problems, with more rounds as you improve things. Use more for different user groups.
• Tasks: realistic goals, not instructions: "You want to book a table for Friday evening" instead of "Click Book Now".
• Prototype or product ready, and a quiet place or video call.
• Consent, privacy and permission to record.

Run:

1. Welcome them, and explain you are testing the design, not them.
2. Ask them to think aloud.
3. Give a task, then stay quiet. Do not help or explain.
4. Observe: where do they hesitate, make errors or give up?
5. Ask a few follow-up questions at the end.
6. Thank them.

Note successes, errors, time and comments. Have a second person take notes if possible.

Analyse and prioritise

Group problems by screen or theme, and rate each by:

• Frequency: how many users hit it?
• Impact: does it block the task, or just slow it?
• Persistence: does it keep happening, or only once?

A simple severity scale: blocker, major, minor, cosmetic. Fix blockers and major problems first. Write each finding as observation, evidence, suggested fix: "3 of 5 users could not find the save button (it was an icon without a label). Add the text 'Save'."

Pitfalls

• Leading participants or explaining things
• Testing friends who are not like real users
• Treating one person's opinion as the truth
• Testing too late, when changes are expensive
• Ignoring results that contradict what you hoped

Remote and unmoderated tests

Tests can be done by video call or with tools where people complete tasks alone. They reach more people and are cheaper, but you lose the chance to ask follow-ups. Choose based on your question.

Try it yourself

Pick a website. Run a heuristic review of one task, listing five issues with the heuristic each breaks. Then ask two people to try the same task while thinking aloud, and compare what they struggled with against your list.

Summary

• Nielsen's ten heuristics provide a fast expert review, but they are not proof of real user behaviour.
• Usability tests watch real people do realistic tasks, with think-aloud and no helping.
• Prioritise problems by frequency and impact, and write findings as observation, evidence and fix.