050 Fitts’ Law
The time required to touch a target is a function of the target size and the distance to the target.
• Proposed by American psychologist Paul Fitts.
• Used to model pointing to an object or computer screen using your finger or pointing device.
• The law is predictive over a wide variety of conditions, devices, and people.
• The primary implication of Fitts’ law is that close, large targets can be accessed more quickly and with fewer errors than distant, small targets.
• Constraints can effectively increase target size. For example, a dropdown menu located at the top of a computer display effectively has infinite height because the screen edge stops the cursor.
• Consider Fitts’ Law when designing controls and control layouts. Keep controls close and large when speed or accuracy is important.
See Also Constraints • Errors • Hick’s Law • Performance Load
