Fat finger

target occlusion

and physical fatigue often reduce the precision of touch input

and these factors might degrade mobile handheld touch conditions. This study aims to identify strategies by which to improve the accessibility of small target selection and touch input precision. Moreover

this work empirically investigates and compares the performances of these strategies. The tilt and movement acceleration detection function of mobile touch devices is used to explore the performance

characteristics

and suitable usage of four kinds of target selection techniques

namely

direct touch

shift & zoom

tilt

and attraction. Direct touch is a baseline technique used only for comparison. The other three are techniques proposed to improve target selection. The subjects used the longest time to select the target and to produce brief finger movement displacement. However

few selection errors were committed with the tilt technique. Shift & zoom was ranked as the most favored technique according to user evaluations. Attraction technique exhibited least selection errors and shortest selection time. The subjects committed the highest number of selection errors with direct touch technique. The targets located in the northwest or southwest corners of the screen are likely to be successfully selected. The following are the average selection time

error rate

and subjective evaluation of the four target selection techniques: 86.06 ms

62.28%

and 1.95; 1 327.99 ms

6.93%

and 3.87; 1 666.11 ms

7.63%

and 3.46; and 1 260.34 ms

6.38%

and 3.74. The three improved target selection techniques outperform direct touch. Each method presents individual characteristics and discrepancies. This study presents guidelines for touch interaction design on mobile devices in target selection.