10 Usability Heuristics (Nielsen)

Developed in 1994 by Dr. Jakob Nielsen, these ten heuristics remain the foundational evaluation rubric for interactive software:

1. Visibility of System Status

The system should always keep users informed about what is going on, through appropriate feedback within reasonable time:

• Example: Progress bars during uploads, breadcrumb trails indicating location, and immediate loading spinners.

2. Match Between System and the Real World

The system should speak the users' language, with words, phrases, and concepts familiar to the user, rather than system-oriented terms:

• Example: Using 'Trash / Recycle Bin' and folder icons, avoiding technical jargon like 'SQL execution timeout'.

3. User Control and Freedom

Users often make mistakes and need a clearly marked 'emergency exit' to leave unwanted states without an extended dialogue:

• Example: Universal support for Undo (Ctrl+Z), easily discoverable 'Cancel' buttons in modal dialogs, and draft auto-recovery.

4. Consistency and Standards

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform and industry conventions (Jakob's Law):

• Example: Underlined blue text always signifies a link; destructive actions consistently use danger red styling.

5. Error Prevention

Even better than good error messages is a careful design which prevents a problem from occurring in the first place:

• Example: Date pickers preventing impossible dates, email fields validating format in real time, and asking for confirmation before deleting accounts.

6. Recognition Rather Than Recall

Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another:

• Example: Autocomplete search suggestions, recently viewed items list, and visible dropdown menus rather than hidden command codes.

7. Flexibility and Efficiency of Use

Accelerators—unseen by novice users—may often speed up the interaction for expert users such that the system caters to both inexperienced and experienced users:

• Example: Keyboard shortcuts (Cmd+K), swipe gestures, and customizable dashboard widgets.

8. Aesthetic and Minimalist Design

Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility:

• Example: Clean, focused checkout screens that strip unnecessary header links and promotional banners.

9. Help Users Recognize, Diagnose, and Recover from Errors

Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution:

• Bad: Error: Invalid parameter syntax (code 0x8004)
• Good: The password must contain at least 8 characters and one number. Please update and try again.

10. Help and Documentation

Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.

A Heuristic Evaluation is an expert review methodology where 3 to 5 usability specialists independently inspect an interface against Nielsen's 10 heuristics.

Nielsen's Usability Severity Scale

• 0 - Not a usability problem: Does not affect user task completion.
• 1 - Cosmetic problem only: Need not be fixed unless extra time is available.
• 2 - Minor usability problem: Low priority; causes slight user hesitation.
• 3 - Major usability problem: High priority; users experience significant friction or abandonment.
• 4 - Usability catastrophe: Imperative to fix before release; prevents users from completing primary transactions.

Multiple evaluators are essential: 1 evaluator typically finds ~35% of usability defects, while 3 to 5 evaluators uncover 75% to 85% of all problems.