Effect of Touch Screen Target Location on User Accuracy

Leahy, Michael and Hix, Deborah (1990) Effect of Touch Screen Target Location on User Accuracy. Technical Report TR-90-48, Computer Science, Virginia Polytechnic Institute and State University.

Abstract

Users can be frustrated by touch screen applications that inaccurately record their touches. Enlarging touch sensitive regions can improve touch accuracy, but few specific quantitative guidelines are available. This paper reports on a controlled experiment that investigated the effect of target location and horizontal viewing location on user accuracy. Measurements showed that persons tended to touch below the target, with touch distance increasing as the target location moved down the screen. In addition, they tended to touch toward the sides of the screen. Using collected data for each of nine screen sectors, graphs were prepared that show the relationship between touch target size and expected accuracy. For example, a 36 mm-squared target in the top left sector would be expected to record accurately 99% of its touches. The empirically-derived, quantitative guidelines will help designers create screens that decrease user errors and frustrations.