An investigation of the usability of the stylus pen for various age groups on personal digital assistants

Many handheld devices with stylus pens are available in the market; however, there have been few studies which examine the effects of the size of the stylus pen on user performance and subjective preferences for handheld device interfaces for various age groups. Two experiments (pen-length experiment and pen-tip width/pen-width experiment) were conducted to determine the most suitable dimensions (pen-length, pen-tip width and pen-width) for a stylus pen among young adult, child and older users. In pen-length experiment, five pen-lengths (7, 9, 11, 13 and 15 cm) were evaluated for young adult, child and older users, respectively. In pen-tip width/pen-width experiment, six combinations of three pen-tip widths (0.5, 1.0 and 1.5 mm) and two pen-widths (4 and 7 mm) were compared for young adult, child and older users, respectively. In both experiments, subjects conducted pointing, steering and writing tasks on a PDA. The results were assessed in terms of user performance and subjective evaluations for all three pointing, steering and writing tasks. We determined that the most suitable dimensions of the pen are as follows: pen-length 11–15 cm, pen-tip width 1.0–1.5 mm and pen-width 7 mm for older users; for child users, pen-length 7–13 cm, pen-tip width 1.0–1.5 mm and pen-width 4 mm; and for young adult users, pen-length 11 cm, pen-tip width 0.5 mm, and pen-width 7 mm.