Target Size, Location, Sampling Point and Instructional Set: More Effects on Touch Panel Operation

Abstract

Accuracy of input using touch panel devices is affected by a number of variables which include device type, target size, and target location. It was also hypothesized that instructional set should influence performance. A screening experiment using a central-composite design (CCD) was conducted to further examine the effects of target position and size upon accuracy of the touch input. Results suggest that error for right-handed users is least near the resting position of the hand (lower right corner of display) and that shortest response times could also be obtained there. Variations in size were more likely to affect error in the y axis and quadratic effects were present. It was also found that although instructions requiring higher precision of input from the operator did not substantially affect bias error, they did produce a reduction in variable error. It is recommended that for applications having established key input areas, positions along the lower and right-hand borders of the control/display unit should be used to minimize activation time and error. Use of the lower border exclusively can accomodate users with either a right-hand or left-hand preference. Some comments are also provided on the limitations which bound the interpretation of results in several studies and inferences thus drawn.