## 5 Data Collection and Analysis
### Behavioral Task Performance Using Task Completion Time and Task Accuracy  
Task performance was assessed using two measures: task completion time and task accuracy. Task completion time was measured using a standardized ratio between task completion time with interruptions and without interruptions as a quantitative performance measure [59]. While task completion time was measured regardless of task type, task accuracy was measured with different outcomes for each type of task. In cognitive tasks, task accuracy could be assessed based on the answers per task, and, in skill tasks, the number of typographical errors represented the task accuracy. Thus, task accuracy was evaluated based on the percentage of false responses in cognitive tasks and typographical errors in skill tasks, and it was standardized using measures with interruptions and without interruptions [59]. Similar to cognitive workload analysis, a two-way repeated-measures ANOVA was conducted for task completion time measures. [PERSON]'s test checked if the sphericity assumption was violated in task completion time measures (time performance ratio, TPR) for the effect of interruption mode (\(\chi^{2}\) (5) = 9.281, \(p\) > 0.05) and the effect of task set (\(\chi^{2}\) (2) = 5.124, \(p\) > 0.05), and the interaction between interruption mode and task set (\(\chi^{2}\) (27) =37.262, \(p\) > 0.05). Therefore, no corrections to degrees of freedom were needed. It also showed a significant effect of interruption modes (F (2, 1225) = 4.71, \(p\) < 0.01) and task sets (F (3, 1224) = 5.29, \(p\) < 0.01) on task completion time. No interaction effect was observed. Post hoc LSD comparisons showed that the TPR of cognitive primary task sets (cognitive/cognitive and cognitive/skill sets) was significantly higher than skill primary task sets (skill/cognitive and skill/skill sets) in the immediate mode. Similar patterns were shown in the scheduled mode; however, in the negotiated mode, the results of both task sets were not significantly different. Regarding the effect of interruption mode, the scheduled mode (mean = 116.28, SD = 12.01) took the shortest task completion time, and the negotiated mode took the longest time (mean = 168.84, SD = 9.97). This suggests our participants spent more time completing task sets in the immediate mode, and they spent less time in the scheduled and mediated modes. For task sets, skill primary task sets took a similar length of task completion time. Descriptive statics of task completion time can be found in Table 5 and Figure 6.  
Figure 5: NASA TLX data by task set and interruption coordination mode. Interruption mode and task set significantly affected task accuracy. Similar to task completion time, the results of a two-way repeated-measures ANOVA revealed statistically significant differences in each subject's task accuracy among task sets, (F (\(3,274\)) = 27.300, \(p<0.05\)) and interruption modes (F (\(2,275\)) = 7.85, \(p<0.001\)). There was no interaction effect between interruption mode and task set. [PERSON]'s test showed that the sphericity assumption was well maintained in task accuracy (wrong answer rate ratio, WARR; and typo rate ratio, TRR) for the effect of interruption mode (\(\chi^{2}\) (5) = 8.985, \(p>0.05\)) and the effect of task set (\(\chi^{2}\) (2) = 5.743, \(p>0.05\)), and the interaction between interruption mode and task set (\(\chi^{2}\) (27) = 31.641, \(p>0.05\)). Therefore, no corrections to degrees of freedom were needed. Descriptive statics of task accuracy can be found in Table 6 and Figure 7.  
According to post hoc LSD paired comparisons, task accuracy showed different patterns by task set and interruption mode. The task accuracy of skill primary task sets was lower than that of cognitive primary task sets in the immediate and the scheduled modes, but there was no difference between the skill/skill task set and skill/cognitive task set in the scheduled mode. In addition, in the negotiated mode, there was no statistical difference of task accuracy in all four task sets.