The input efficiency of chord keyboards

This study focused on an innovative mobile input device model that integrated ergonomic design principles to create a chord keyboard for use in concert with pointing devices. We conducted usability tests to demonstrate the operating performances of such keyboards using keys with four characters per key. Twelve right-handed subjects between the ages of 20 and 30 years and with no wrist disability participated in the usability tests. We analyzed the resulting data to compare the differences among the means. The results indicated that keyboards with multiple characters per key created some confusion among users but that keys with multiple characters per key nonetheless resulted in better input performance.