User Performance and Satisfaction of Tablet Physical Keyboards

This study presents an evaluation of user performance and satisfaction of three physical keyboards that accompany two popular tablet computers. All keyboards were dual purpose in that they served as tablet covers in addition to typing input devices. The keyboards varied in weight, thickness, and key travel. The thinnest keyboard featured durability and pressure-sensitive keys while the other two keyboards were slightly thicker, but used mechanical keys. Participants unfamiliar with the keyboards were asked to type a series of phrases on each keyboard after a short practice. Typing performance, and perceived usability and workload were assessed. Results show a clear advantage in both performance and satisfaction for the mechanical-key keyboards. Users demonstrated typing speeds approximately 10 words per minute (WPM) slower and were prone to typing errors such as incorrect key substitutions, omissions, and inadvertent insertions with the thinner, pressure-sensitive

keyboard. In addition, users reported the flat keyboard was more mentally demanding, more frustrating, and required more effort to use. Results from this study reveal the importance of tactile feedback to user typing performance and satisfaction. Designers of tablet physical keyboards must assess the tradeoff between optimal keyboard size, weight, and thickness, and a design that affords accurate typing.