Cursor Deviation

The difference between the actual path taken by a cursor and the ideal straight-line path between the starting point and the target. Cursor deviation is a key performance metric in evaluating alternative input devices such as head controls, eye trackers, and adapted mice. Higher cursor deviation indicates reduced precision in cursor control and may result from involuntary movements, limited motor control, or difficulty coordinating the input modality with the intended direction. Measuring cursor deviation alongside speed and accuracy provides a more complete picture of a user's interaction quality than target acquisition metrics alone.