Design Principles

Fitts’s Law

The time required to move to a target is a function of the target size and distance to the target.

Fitts’ Law states that the smaller or farther a target, the longer it takes to accurately point and move to it. It emphasizes the tradeoff between speed and accuracy in movement, affecting control design and layout efficiency, especially in rapid, precise tasks like using a mouse or touchscreen.

Poor design: The dropdown is on the left, and the "Add" button is far on the right, making the user travel across the screen to complete a task
Good design: the dropdown is on the left, and the "Add" button is far on the right, making the user travel across the screen to complete a task
Takeaways
  • Larger, closer targets improve accuracy and speed: Controls should be designed to be easily reachable or larger to reduce errors.
  • Position buttons at screen edges or corners: These areas limit movement, making selection faster and more accurate.
  • Minimize homing movements: Reducing fine adjustments during movement enhances performance and reduces mistakes.

Performance VS Preference

Proximity

Hick’s Law

Flexibility-Usability Tradeoff