Usability is a measure of how effectively a user interface can be used. An interface is considered usable when it is easy, efficient, and effective to understand and use.
Who: System administrators
When to Apply Usability and Interface Design Principles
Use these principles when:
- Evaluating the impact of configuration changes on system usability.
- Configuring a portal, form, or workflow and want to apply usability principles.
- End users report difficulty navigating or using the system.
What Is UI?
The User Interface (UI) is the collection of screens, buttons, icons, and text that users interact with. Changes to the UI occur when a custom field is moved, a button is added, or a color is changed.
Key questions for evaluating UI:
- Is there sufficient color contrast?
- Is the content concise and easy to read?
- Is the layout organized with adequate white space?
- Are the pages responsive?
- Is the interface compatible with assistive technology?
What Is UX?
User Experience (UX) encompasses all aspects of a user's interaction with an organization, its services, and its products. Improving a process to make it easier or faster is an improvement in UX.
Key questions for evaluating UX:
- Can users accomplish their intended task easily, quickly, and simply?
- Do users genuinely want to use this product or service?
- Do users trust and value this product or service?
Usability Issues
A usability issue is any factor that prevents a system from being easy, efficient, and effective to learn and use. Usability issues are objective, not subjective preferences such as a dislike of a particular color. For example, a usability issue may be a contrast ratio that fails Web Content Accessibility Guidelines (WCAG).
Established standards called heuristics are used to evaluate the usability of user interface designs. The 10 heuristics in the next section, originally formulated by Jakob Nielsen in 1990, remain a widely used benchmark in interface design.
Heuristics for User Interface Design
The following heuristics outline the core principles for evaluating and improving the usability of an interface.
Visibility of System Status
Users need to know what is happening, what is expected of them, and what comes next.
Ways to address the visibility of system status:
- Indicate progress, including how far along and what remains.
- Display space or time remaining.
- Draw attention to changes.
- Communicate what action is expected of the user.
- Provide status updates on the current state of elements.
Match Between the System and the Real World
Use language and concepts familiar to users rather than internal or technical terminology. Present information in a logical, comprehensible way that matches user expectations.
Ways to match between the system and the real world:
- Use familiar words, phrases, and concepts.
- Follow established conventions.
- Organize information logically.
- Provide previews or representations of content.
User Control and Freedom
Users make accidental clicks. Provide clear ways to exit, undo, or go back so users are not left in an undesirable state.
Ways to address user control and freedom:
- Provide undo and redo options.
- Offer multiple ways to navigate or find information, such as searching, filtering, and view options.
- Allow users to exit processes by including options like cancel, close, and exit.
Consistency and Standards
Buttons and links should be consistently named, placed in predictable locations, and follow industry standards.
Ways to address consistency and standards:
- Keep links, buttons, and information in the same order and location.
- Use the same labels for links and shortcuts when multiple paths lead to the same destination.
Error Prevention
Help users avoid errors before they occur. If an action results in significant changes, inform the user and provide a path forward.
Ways to address error prevention:
- Provide necessary information and warnings.
- Ensure links and buttons describe their actions accurately.
- Remove conditions that lead to errors or alert users when they occur.
- Refine processes to minimize errors.
Recognition Rather Than Recall
Reduce cognitive load by making actions, options, and information visible rather than requiring users to remember them from elsewhere.
Ways to address recognition rather than recall:
- Make objects, actions, options, and directions visible or easily retrievable.
- Avoid relying on user memory.
- Eliminate codes and unnecessary steps.
- Provide visual representations.
Flexibility and Efficiency of Use
Help users complete tasks more quickly by providing shortcuts and default options.
Ways to address flexibility and efficiency:
- Provide shortcuts for frequently used functions.
- Offer default options.
- Use list views with available options where applicable.
Aesthetic and Minimalist Design
Every element on a page competes for attention. Remove or simplify anything that is not essential to helping users complete their goal.
Ways to address aesthetic and minimalist design:
- Place essential information above the fold, which is the initial viewable area.
- Minimize the signal-to-noise ratio.
- Be selective with color and imagery.
- Remove redundant content.
Help Users Recognize, Diagnose, and Recover from Errors
When an error occurs, indicate that an error has occurred through a visual message, explain the problem in plain language, and provide a pathway to resolve it.
Ways to help users recognize, diagnose, and recover from errors:
- Use plain language in all messages.
- Always provide or suggest a solution.
- Explain what happened and why.
- Offer a clear path to resolution.
Help and Documentation
Systems should ideally work without requiring users to read documentation. When documentation is necessary, ensure it is available in context, outlines concrete steps, and is concise.
Ways to address help and documentation:
- Provide context-sensitive help.
- Offer examples and recommendations.
- Highlight new or changed features.
- Provide additional guidance where needed.
- List concrete steps.
- Keep instructions brief and concise.
Resources
For information about usability and interface design, see: