Size Effects on the Usability of Tablets in Pointing and Typing Tasks

摘要

In 2014, with increasing use of multi-purpose, tablets remain the leading entry points of mobile connectivity for global consumers. It is expected to see more competitive overlap among display sizes for tablet PCs, notebook PCs, and smartphones. In fact, no matter what type of task is applied, the size effect impacts productivity, portability and user's experience of device usage on any form factors of mobile devices. However, research seldom studied the size effects regarding the trade-offs between performance and portability of tablets. To further investigate the size effects of the display and touchscreens on their performances, this study compared the operation time and error rate for the touch-input methods of 3 different sizes of tablets in 3 applied tasks. Our lab's study on the usage of tablets showed that browsing the Internet, shopping online, watching videos, viewing and editing email (words processing and/or photos sharing) were the most common applications mostly using online real-time communication software, Internet browsers and other related software. This result was used as the base to design the applied tasks of the present study. Accordingly, the software and task types were divided into multi-direction pointing and tapping, multi-direction dragging and dropping, and on-screen typing. Overall, it seems that the closer the sizes of displays and on-screen keyboards to those sizes of a generic laptops, the shorter the operation times. As these objective measures confirmed by the subjective assessments, the 10.1” tablets was most preferred; while the differences in the satisfactions were not significant among the three tablets. The results rationalized the phenomena in the tablet PC market that the 8.1” and 10.1” diagonal screens were popular especially for applied tapping tasks (e.g., Internet browsing) and on-screen typing tasks (e.g., word processing for email messages), respectively.