Evaluation of Mouse, Rate-Controlled Isometric Joystick, Step Keys, and Text Keys for Text Selection on a CRT

Four devices are evaluated with respect to how rapidily they can be used to select text on a CRT display. The mouse is found to be fastest on all counts and also to have the lowest error rates. It is shown that variations in positioning time with the mouse and joystick are accounted for by Fittss Law. In the case of the mouse, the measured Fittss Law slope constant is close to that found in other eye-hand tasks leading to the conclusion that positioning time with this device is almost the minimal achievable. Positioning time for the key devices is shown to be proportional to the number of keystrokes which must be typed.