The Design and Evaluation of a High-Performance Soft Keyboard

The design and evaluation of a high performance soft keyboard for mobile systems are described. Using a model to predict the upper-bound text entry rate for soft keyboards, we designed a keyboard layout with a predicted upper-bound entry rate of 58.2 wpm. This is about 35% fasterthan the predicted rate for a QWERTY layout. We compared our design (“OPTI”) with a QWERTY layout in a longitudinal evaluation using five participants and 20 45-minute sessions of text entry. Average entry rates for OPT1increasedfrom 17.0 wpm initially to 44.3 wpm at session20. The averagerates exceededthose for the QWERTY layout after the 10”’ session(about4 hours of practice). A regressionequation (R’ = .997) in the form of the power-law of learning predicts that our upper-bound prediction would be reach ataboutsession50. Keywords Soft keyboards,mobile systems,stylus input, pen input, linguistic models,Fitts’ law, digraph probabilities

• Type: Conference
• Year: 1999
• Where: CHI
• Authors: I. Scott MacKenzie, Shawn X. Zhang
• Keywords: CHI 1999, Entry Rates, Human Computer Interaction, QWERTY Layout, Soft Keyboards