Development of a Digram-Based Typing Key Layout for Single-Finger/Stylus Input
James R. Lewis, Peter J. Kennedy, Mary J. LaLomia · Proceedings of the Human Factors and Ergonomics Society Annual Meeting · 1999
Hand-held devices often include a keyboard on which a user types with one finger or a stylus. When a user types with one finger, conventional key layouts are not optimal for typing throughput. We used a predictive human performance model based on the frequency of English-language digrams and interkey distances to evaluate alternative key layouts. We also analyzed English digrams with a path-analysis program to determine the strongest links among English letters. The path analysis combined with the predictive human performance model provided a basis for developing and evaluating typing-key layouts for single-finger input. A nonstandard typing-key layout (in a roughly 5 times 5 key matrix) based on digram analysis should, after the development of skilled use, be about 27% better than the QWERTY layout. A nonstandard alphabetic typing-key layout (in a roughly 5 times 5 key matrix) should be about 13% better than the QWERTY layout for single-finger entry.