Combined and Comparative Metrics - Measuring the User Experience: Collecting, Analyzing, and Presenting Usability Metrics - page 207

Table 8.10 Sample time data from 10 tasks in a usability test showing average actual time per task (in
seconds), expert time per task, and ratio of expert to actual time.
Task Actual Time Expert Time Expert/Actual

1 124 85 69%

2 101 50 50%

3 89 70 79%

4 184 97 53%

5 64 40 63%

6 215 140 65%

7 70 47 67%

8 143 92 64%

9 108 98 91%

10 92 60 65%

Table 8.10 Sample time data from 10 tasks in a usability test showing average actual time per task (in
seconds), expert time per task, and ratio of expert to actual time.

Graphing the ratio of expert to actual times, as shown in Figure 8.8 , makes
it easy to spot tasks where the test participants did well in comparisons to the
experts (Tasks 3 and 9) and tasks where they did not do so well (Tasks 2 and 4).

Ratio of Expert Time to Actual Time

Task 10

Task 9

Task 8

Task 7

Task 6

Task 5

Task 4

Task 3

Task 2

Task 1

0% 20% 40% 60% 80% 100%

Figure 8.8 Graph of the ratio of expert to actual times from Table 8.10 .