Textbook of Usability

Nielsen's 10 usability heuristics, published by Jakob Nielsen in 1994, are the most widely used framework for usability evaluation. Developed through a factor analysis of 249 usability problems, they distil decades of research and practice into ten broad principles:

1. Visibility of system status — keep users informed about what is happening
2. Match between system and the real world — use familiar language and concepts
3. User control and freedom — provide clear "emergency exits" like undo
4. Consistency and standards — follow conventions; don't vary terminology or action
5. Error prevention — eliminate error-prone conditions
6. Recognition rather than recall — make options visible rather than memorised
7. Flexibility and efficiency of use — accelerators for experts, guidance for novices
8. Aesthetic and minimalist design — no irrelevant information
9. Help users recognise, diagnose, and recover from errors — plain-language error messages
10. Help and documentation — searchable, task-focused, concise

The heuristics serve both as design guidelines (informing new work) and as evaluation criteria (for heuristic evaluation, Chapter 16). They overlap significantly with Shneiderman's golden rules and Norman's design principles, providing complementary vocabulary for describing usability failures.

Heuristics are rules of thumb, not guarantees. They can conflict with each other (minimalism vs. recognition) and they cannot predict how a specific design will work for specific users. They are most valuable as a first-pass assessment and for catching common failure patterns.