Configuring a numeric keypad for a touch screen

Abstract This paper reports on a study comparing keying accuracy and speed for eight different numeric keypad configurations on a touch screen. Using touch-sensitive keypads displayed on a computer terminal, operators entered numbers presented to them through a speech synthesizer. Dependent measures collected were keying rates, errors, and the x- and y-dimension standard deviations from the centre point of the key. The primary finding was that keypads with square keys resulted in improved speed and a higher degree of accuracy than do keypads with regular keys (either a long horizontal dimension or a longer vertical dimension). Spread-out versions of the keypads (inter-key spacing = 1·3 cm) did not yield superior performance compared with compressed versions (inter-key spacing = 0·6 cm).