Glossary » Meyer’s Law
T = A + B * SQRT(D/W)
T = time to move to a target
D = distance to target
W = width of target
A ~ -13 msec
B ~ 108 msec
Meyer’s Law is a refinement of Fitts’ Law for predicting the time it takes for rapid aimed movements, such as hitting a button on the screen by moving a mouse to it. (A and B are constants which may vary with the input device.)
Meyer’s Law is derived from a stochastic optimized-submovement model. This model says that movements consist of a primary submovement and a possible corrective secondary submovement toward a target.
Meyer’s Law can be used to make predictions of how much time it will take for a user to accomplish a task involving selection of targets on the screen (such as icons, menus, or hypertext links).
Meyer, D.E. et al (1988). Optimality in human motor performance: ideal control of rapid aimed movements. Psychological Review, 95:3, 340-370.