An empirical comparison of pie vs. linear menus

TLDR

Menus are usually linear, but pie menus arrange items around a circle, exploiting display flexibility. Pie menus cut target seek time, lower error rates, enlarge targets per Fitts's Law, reduce drift distance, and are subjectively comparable to linear menus.

Abstract

Menus are largely formatted in a linear fashion listing items from the top to bottom of the screen or window. Pull down menus are a common example of this format. Bitmapped computer displays, however, allow greater freedom in the placement, font, and general presentation of menus. A pie menu is a format where the items are placed along the circumference of a circle at equal radial distances from the center. Pie menus gain over traditional linear menus by reducing target seek time, lowering error rates by fixing the distance factor and increasing the target size in Fitts's Law, minimizing the drift distance after target selection, and are, in general, subjectively equivalent to the linear style.