Online Appendix to: Two-Handed Marking Menus for Multitouch Devices

Total Time. By day five, the average total time was 805 ms for 1HR and 682 ms for 2HS, reduced from 932 ms and 823 ms respectively on day one. Menu technique (p = .005) and day (p = .009) had significant effects on total time, but there was no interaction effect (F4,16 = 0.308, p = .869). Reaction Time. By day five, the average reaction time was 590 ms for 1HR and 533 ms for 2HS, reduced from 552 ms and 633 ms, respectively. The difference between 1HR and 2HS reaction times dropped from 81 ms to 57 ms (29.6%). Menu technique (p = .012) and day (p < .001) had significant effects on reaction time, but there was no interaction effect (F4,16 = 0.907, p = .483). Movement Time. By day five, the average movement time was 315 ms for 1HR and 149 ms for 2HS, reduced from 380 ms and 190 ms, respectively. The difference between 1HR and 2HS movement times dropped from 190 ms to 166 ms (12.6%). Menu technique (p = .001) had a significant effect on movement time, whereas day did not (p = .277). There was no interaction effect (F4,16 = 1.263, p = .325). Accuracy. By day five, the average accuracy was 98.8% for 1HR and 96.8% for 2HS, increased from 95.2% and 94.8% respectively on day one. The day had a significant effect on accuracy (p = .195) whereas the menu technique did not (p = .195). There was no interaction effect (F4,16 = 1.758, p = .187). Stroke Pairs. Figure 21 shows the total time in sorted order for each of the 16 stroke pairs in the 1HR condition (top) and the 2HS condition (bottom). For 2HS, we find that drawing strokes that are bilaterally symmetric or in the same direction (translationally symmetric), is 18% faster on average than drawing the remaining stroke pairs. For 1HR, we find no large difference in total time between groups of stroke pairs, but the pairs in which both strokes are drawn in the same direction are the four fastest.