Fitt's Law

First time I heard this I thought it was Fitz Law, which meant googling didn't turn up the right stuff. but I got it right eventually eh.

So Fitt's Law is T = a + b log2(1 + D/W), so basically, the closer and bigger it is, the easier it is to point at something. It was proposed by Paul Fitts back in 1954

Anyway, Fitt's law is very interesting in that it provides a rigid quantification of Human Computer Interaction. In a field permeated with ethnographies and questionnaires, and fuzzy measurements, it was good to know that something exact could be deduced.

It has held up remarkably well over time and is very important to CHI, which is full of pointing of various kinds. Unless your using a keyboard or voice, pretty much all other interfaces involve pointing (mostly because of buttons). It things like this that contribute to CHI becoming a harder science.