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Updated: Aug 19, 2026

An Assessment Method and Toolkit to Evaluate Keyboard Design on Smartphones
Published on: October 5, 2020
Usability of a one-hand ternary chord keyboard
1Industrial Ergonomics Laboratory, Human Factors Engineering Center, Industrial and Systems Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0118, USA.
Abstract:
Five subjects learned to operate a one-hand ternary chord keyboard with 18 different characters, on average, in just over 30 min. Subjects practised inputting numeric-type text for an additional 60 h and attained an average peak keying speed of 170 characters/min. Because of the short learning time, high performance, and low space requirement, the one-hand ternary chord keyboard is an attractive input device for tasks with small character sets.
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