Keystrokes Per Character

A metric used to evaluate the efficiency of text-entry methods by measuring the average number of keystrokes required to produce each character of text. A lower KSPC indicates a more efficient input method. For standard MultiTap on a 12-key phone keypad, the theoretical best KSPC varies depending on the navigation strategy used — for example, a 2-way navigation approach has a different optimal KSPC than a 4-way approach. KSPC is particularly important in accessibility research for evaluating alternative text-entry methods designed for users with disabilities, as it directly affects typing speed, effort, and fatigue.