Fitts’s Law and Interface Design
Sunday, August 31st, 2008
How many of you have heard about Fitts’s Law? The opening paragraph in Wikipedia describes it as the time required to rapidly move to a target area, as a function of the distance to the target and the size of the target
. In even more simple terms it means the larger the button and the closer it is the easier you can click it with your mouse, finger, joystick or hockey stick. The smaller it is and the further away the harder it is to click. Which, when you think about it is pretty obvious.
Particletree had a feature article about Visualizing Fitts’s Law (by Kevin Hale) about a year ago which provides a fresher perspective than Wikipedia, but it’s also worth spending 14 minutes listening to Jared Spool’s Usability Tools Podcast: Applying Fitts’ Law.
If you want something to be easy to click then you make it bigger and closer
, as Jared puts it. If you want something to be harder to click then you make it smaller and put it further away
.
Paul Fitts, a psychologist, published Fitts’s Law in 1954 after studying the way people interacted with airplane cockpits. As a model of human psychomotor behaviour it seems to work on just about everything you can think of - including interfaces. Listen to Jared’s podcast, it will make a lot of sense.
