A good user interface

Recently, someone inquired about the characteristics of a good user interface. While many hope for a straightforward checklist reminiscent of a car maintenance guide, designing an effective UI is more intricate. Beyond quantifiable elements, UI design interweaves with sociological and psychological nuances.

In this article, I will distill the essence of UI design into key considerations:

  1. Clarity: Every element should clearly convey its purpose and function, eliminating guesswork for users.
  2. Consistency: Maintaining a uniform design and interaction across the interface aids predictability.
  3. Feedback: Users must always receive confirmation of their actions, be it through button presses or error messages.
  4. Accessibility: The UI must cater to everyone, incorporating features like readable fonts and compatibility with screen readers.
  5. Efficiency: Aim to streamline the user journey, minimizing steps or actions to achieve goals.
  6. Error Handling: When issues arise, provide clear error messages and potential solutions.
  7. Flexibility: While allowing user customization, also establish intuitive defaults.
  8. Aesthetic Appeal: A harmonious blend of color, typography, and imagery can elevate the user experience.
  9. Responsiveness: Ensure the UI performs consistently across various device sizes and responds swiftly to interactions.
  10. Discoverability: Essential features should be prominently placed and easy to locate.
  11. Safety: Protect users from unintended actions with safety nets like deletion confirmations.
  12. Simplicity: Embrace the philosophy that less is often more, avoiding unnecessary complexities.
  13. Guidance: Offer assistance for complex interfaces, whether through onboarding tours or tooltips.
  14. Intuitiveness: Align the interface with user expectations based on similar experiences.
  15. Testing: Regularly solicit feedback and conduct tests with actual users to refine the design.

Diving deeper into the art and science of UI design:

  • Cultural Considerations: Recognize that user expectations can vary across cultures. A design that’s intuitive in one region may be perplexing in another. It’s vital to approach UI design with a global perspective, ensuring cultural appropriateness and effectiveness.
  • Psychology of UI: A deeper understanding of human psychology can yield interfaces that resonate more with users. Grasping how users think, process information, and make decisions can make a UI more intuitive and engaging.
  • Importance of Typography: Typography isn’t just about choosing a font. It’s about readability, mood, and message. Thoughtful typographic decisions can influence user engagement and comprehension.
  • Color Theory: Colors evoke emotions and drive actions. Being aware of color psychology and ensuring a harmonious palette can enhance user experience, guide user attention, and even influence decisions.

Remember, while this checklist offers a solid foundation, UI design’s true essence lies in understanding and empathizing with users. Tailoring interfaces to meet their needs, preferences, and expectations ensures a more fulfilling and effective user experience.

Quantitative Metrics

  1. Clarity:
    • 1: Most UI elements are confusing; users consistently ask how to use the interface.
    • 10: Every UI element is self-explanatory; users navigate seamlessly without assistance.
  2. Consistency:
    • 1: Inconsistent UI elements and interactions; users have to relearn behaviors.
    • 10: Uniform design and interactions throughout, promoting user predictability.
  3. Feedback:
    • 1: Rarely offers feedback; users often unsure if actions were successful.
    • 10: Immediate and clear feedback for every interaction.
  4. Accessibility:
    • 1: Hardly accessible for users with disabilities; no compatibility with assistive technologies.
    • 10: Fully accessible, passes all WCAG guidelines, and offers a seamless experience for all users.
  5. Efficiency:
    • 1: Tasks require excessive steps or actions; processes are convoluted.
    • 10: Streamlined user journey; minimum actions needed to achieve goals.
  6. Error Handling:
    • 1: Uninformative error messages; users left clueless during issues.
    • 10: Clear error messages with actionable solutions provided.
  7. Flexibility:
    • 1: Rigid interface with no customization options.
    • 10: Highly customizable with user-friendly default settings.
  8. Aesthetic Appeal:
    • 1: Jarring design with poor color combinations and typography.
    • 10: Visually pleasing, harmonious design enhancing user experience.
  9. Responsiveness:
    • 1: Slow performance; poor adaptability across devices.
    • 10: Swift, smooth performance with excellent adaptability on all devices.
  10. Discoverability:
  • 1: Vital features hidden or hard to locate.
  • 10: Intuitive layout; essential features prominently displayed and easily found.
  1. Safety:
  • 1: Easy to make irreversible mistakes without warnings.
  • 10: Safety nets in place, ensuring user confirmation for critical actions.
  1. Simplicity:
  • 1: Overly complex, bloated with unnecessary features.
  • 10: Clean, minimal design focusing on essential features.
  1. Guidance:
  • 1: No assistance for navigating complex aspects.
  • 10: Comprehensive guidance, with onboarding tours or tooltips available.
  1. Intuitiveness:
  • 1: Interface consistently defies user expectations.
  • 10: Aligns perfectly with user expectations based on similar experiences.
  1. Testing:
  • 1: No feedback loop; evident unaddressed user experience issues.
  • 10: Regular user feedback integrated, with ongoing tests and refinements.

1. Testing Individual Screens


  • Design and Layout: Assess if elements are organized logically.
    • Example: On a login screen, are the username and password fields clearly visible and positioned logically above the “Login” button?
  • Content: Check clarity of text, icons, and imagery.
    • Example: Does the icon for “settings” universally represent what users expect for a settings option?
  • Interactions: Observe interactions with screen elements.
    • Example: Does the hover effect on a dropdown menu provide clear feedback that it’s interactive?


  • First Click Testing: Identify initial user interactions.
    • Example: Upon seeing the homepage, where does the user click first? Is it the “Start Here” button or the “FAQ” section?
  • Preference Testing: Present design variations.
    • Example: Which color scheme do users prefer for the dashboard: a dark theme or a light one?
  • Visual Clarity Assessments: Have users describe elements.
    • Example: Ask users what they believe a specific ambiguous icon represents.

Feedback to Collect:

  • Element Visibility: Identify standout elements.
    • Example: Users might consistently notice an animated banner but miss the static “Help” button.
  • Intuitiveness: Check if design choices align with expectations.
    • Example: Users might expect the logout button in the top-right corner, not buried in a menu.
  • Confusions/Clarifications: Clarify ambiguous elements.
    • Example: Users might be unsure if a slider bar changes volume or brightness.

2. Testing Processes through the Application


  • Flow and Sequence: Understand user navigation paths.
    • Example: During a product purchase process, do users seamlessly move from selection to checkout?
  • Achieving Goals: See how users perform tasks.
    • Example: How easily can a user set up a profile and add a profile picture?
  • Feedback and Guidance: Assess feedback during user navigation.
    • Example: If a user enters an incorrect password, is the error message helpful?


  • Task Completion: Assign and observe tasks.
    • Example: Ask users to find and use the tool for exporting data.
  • Scenario Testing: Provide use cases.
    • Example: “You want to change your account email. How would you do that?”
  • Error Testing: See if feedback is clear.
    • Example: If users try to upload an oversized image, does the app inform them of the size limit?

Feedback to Collect:

  • Navigation: Assess intuitiveness.
    • Example: Users might struggle to find the “Previous Orders” section if it’s not clearly labeled.
  • Points of Friction: Spot challenges.
    • Example: Users might get confused if the payment gateway takes too long without a loading indicator.
  • Feedback Appreciation: Assess clarity of feedback.
    • Example: Users might appreciate a clear confirmation message after successfully updating settings.

Key Differences to Remember:

  • Depth vs. Breadth: Screen testing is detail-oriented, whereas process testing is holistic.
    • Example: Screen test might focus on the design of a “Submit” button, while a process test might see how that button integrates into the entire form submission experience.
  • Duration: Screen tests might be shorter.
    • Example: Testing a contact form’s design might take 5 minutes, but testing the entire process of inquiry submission and receiving a confirmation might take 15 minutes.
  • Objective: Screen tests refine specifics; process tests optimize the journey.
    • Example: A screen test might refine the wording of a CTA, while a process test might streamline the entire signup flow.

Combining both data types—like completion times (quantitative) and user feedback (qualitative)—provides a fuller usability picture.