Keystroke Saving Rate

A metric measuring the efficiency of text prediction systems by calculating the percentage of keystrokes saved compared to typing the same text on a standard keyboard without prediction. A KSR of 50% means the user needed only half the keystrokes they would have required otherwise. This measure is critical for evaluating AAC devices and assistive text entry systems, as higher KSR values indicate reduced physical effort—particularly important for users with motor impairments who may fatigue quickly or have limited movement range.