Keystroke Saving

A metric used to evaluate word prediction and word completion systems, measuring the percentage of keystrokes that a user can avoid by accepting system predictions instead of typing each character individually. Keystroke saving is calculated by comparing the number of keystrokes needed with the prediction system to the number needed without it. For users with physical disabilities who rely on slow input methods such as single-switch scanning, head pointers, or eye tracking, even small improvements in keystroke saving can significantly reduce fatigue and increase communication speed. However, keystroke saving alone does not capture the full picture of system effectiveness, as the cognitive effort required to evaluate and select predictions also affects overall communication rate.