Data entry for mobile devices: An empirical comparison of novice performance with Jot and Graffiti

In this article, we report on an empirical comparison of two common gesture recognition techniques. Thirty-one novices completed six realistic tasks using either Jot or Graffiti. An analysis of error-corrected data entry rates indicates that participants using Jot completed the tasks significantly faster than those using Graffiti. An analysis of uncorrected errors yielded no significant differences while several questions assessing subjective satisfaction yielded significantly more positive results for Jot. A new event called Period of Difficulty (PoD) is proposed to help identify situations were novices experience significant difficulty. Users experience more PoD when entering basic alphanumeric characters using Graffiti than they do using Jot. In contrast, Jot users experience more PoD when entering symbols than Graffiti users. Further, a detailed analysis of the PoD provides insights regarding the definition and use of the inherent accuracy metric while highlighting opportunities to improve the underlying technologies. We conclude by providing specific recommendations for improving the usability of Jot and Graffiti for novice users and outlining several additional directions for future research.