NielsenConsistency [principle] v1.0.0

Nielsen Heuristic 4: users should not have to wonder whether different words, situations, or actions mean the same thing; follow platform and industry conventions.

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

Meta

• License: LicenseRef-Citation-Only AND Apache-2.0
• License Provenance: package-authorship-claim

Attributed To

Jakob Nielsen, 1994

Applies To

• icon usage: same icon for same action across all screens
• color semantics: red = error/danger used uniformly, not decoratively
• keyboard shortcuts: matching OS conventions (Cmd+S, Ctrl+Z)
• terminology: using one term for one concept throughout all UI copy
• interaction patterns: identical controls behave identically everywhere
• component libraries: enforcing internal consistency via a design system

Counter Examples

• A SaaS product where the primary action button is blue in the dashboard, green in settings, and purple in onboarding — users lose confidence in which button is 'safe'.
• An app where Escape closes modals in some flows but does nothing in others — users can't form a reliable mental model.
• Different pages calling the same object 'Project' in one place and 'Workspace' in another, creating permanent user confusion about whether they're the same thing.

NielsenConsistency [principle] v1.0.0

Nielsen Heuristic 4: users should not have to wonder whether different words, situations, or actions mean the same thing; follow platform and industry conventions.

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

Meta

• License: LicenseRef-Citation-Only AND Apache-2.0
• License Provenance: package-authorship-claim

Attributed To

Jakob Nielsen, 1994

Applies To

• icon usage: same icon for same action across all screens
• color semantics: red = error/danger used uniformly, not decoratively
• keyboard shortcuts: matching OS conventions (Cmd+S, Ctrl+Z)
• terminology: using one term for one concept throughout all UI copy
• interaction patterns: identical controls behave identically everywhere
• component libraries: enforcing internal consistency via a design system

Counter Examples

• A SaaS product where the primary action button is blue in the dashboard, green in settings, and purple in onboarding — users lose confidence in which button is 'safe'.
• An app where Escape closes modals in some flows but does nothing in others — users can't form a reliable mental model.
• Different pages calling the same object 'Project' in one place and 'Workspace' in another, creating permanent user confusion about whether they're the same thing.

Sources

Examples

• Stripe's dashboard uses a consistent right-side panel drawer for every detail view — users learn this pattern once and apply it everywhere.
• Linear uses the same keyboard shortcut prefix schema (G for 'Go to', C for 'Create') throughout the product — internal consistency reduces the learning curve.
• Apple's Human Interface Guidelines enforce external consistency: swipe-from-left always navigates back, the Home indicator always dismisses to home — no app breaks this.

Relations

related: [@community/principle-nielsen-recognition, @community/principle-nielsen-real-world-match, @community/fact-consistency-standards, @community/fact-gestalt-similarity, @community/example-linear-issues-table, @community/example-radix-tabs, @community/rule-no-terminology-drift]

Source

• Jakob Nielsen, 'Heuristic Evaluation', in Nielsen & Mack (eds.), Usability Inspection Methods (1994)
• https://www.nngroup.com/articles/ten-usability-heuristics/