What is a heuristic evaluation?
Jakob Nielsen and Rolf Molich created the method in 1990. They called it “discount usability”: you don't need to recruit users. A few people look at the site and judge it against a short list of rules. In 1994 Nielsen turned those rules into the 10 usability heuristics. They are still the most used set today.
Nielsen's 10 usability heuristics, with website examples
Visibility of system status
Always show people what is going on, and answer each action fast.
On a website: Loading indicators, confirmation messages, the current page highlighted in the menu.
Match between the system and the real world
Use the words and order that people already know.
On a website: “Basket” and “Checkout” instead of internal jargon; dates in the local format.
User control and freedom
Give a clear way out: undo, cancel and back.
On a website: A visible way to close pop-ups, edit the cart or undo a deletion.
Consistency and standards
Do things the way other sites do them.
On a website: The same button style for the same action everywhere (see Jakob's Law).
Error prevention
Stop mistakes before they happen.
On a website: Input types, constraints and real-time validation in forms.
Recognition rather than recall
Show the options, so people don't have to remember them.
On a website: Visible navigation, recently viewed items, examples in fields.
Flexibility and efficiency of use
Give regular users shortcuts.
On a website: Keyboard shortcuts, saved addresses, filters and search.
Aesthetic and minimalist design
Show only what matters for the task.
On a website: One primary action per screen, no decorative clutter.
Help users recognize, diagnose and recover from errors
Write error messages in plain words that say how to fix it.
On a website: “The card number is too short” next to the field, not a generic error at the top.
Help and documentation
Make help easy to find when it's needed.
On a website: A visible help or contact link, an FAQ near complex decisions.
How to run a heuristic evaluation
Set the scope
Choose the pages and journeys to review and the user goals behind them.
Brief 3–5 evaluators
Give each person the heuristics and the tasks to test. Nielsen found that one person misses most problems. A small group finds most of them.
Evaluate independently
Each person goes through the site at least twice: once to learn the flow, once to look at details. They note each problem with a screenshot.
Merge and rate severity
Combine the lists, remove duplicates and rate each problem on the severity scale below.
Recommend fixes
For each problem, propose a concrete change and an owner.
Severity ratings
| Rating | Meaning |
|---|---|
| 0 | Not a usability problem |
| 1 | Cosmetic problem — fix only if time allows |
| 2 | Minor usability problem — low priority |
| 3 | Major usability problem — important to fix |
| 4 | Usability catastrophe — must fix before release |
Several heuristics can be checked automatically. Lensux checks visible system status signals, error prevention in forms (input types and constraints), help and documentation links, consistency with web conventions and accessibility basics, and rates every finding by severity.
Frequently asked questions
How many evaluators do you need for a heuristic evaluation?
Nielsen recommends three to five. One evaluator finds a minority of problems; adding more increases coverage with diminishing returns after about five.
Is a heuristic evaluation the same as a UX audit?
It is usually one part of a UX audit. A full audit also covers accessibility, performance, analytics data and business goals.
Can heuristic evaluation replace user testing?
No. It finds problems that experts can predict; user testing reveals the ones they can't. Use both.