Combined and Comparative Metrics - Measuring the User Experience: Collecting, Analyzing, and Presenting Usability Metrics - page 200

Table 8.8 Sample standardized data from a usability test a .

SUM

Task Low Mean High Completion Satisfaction Time Errors

Reserve a room 62% 75% 97% 81% 74% 68% 76%

Find a hotel 38% 58% 81% 66% 45% 63% 59%

Check room
rates

49% 66% 89% 74% 53% 63% 74%

Cancel
reservation 89% 91% 99% 86% 91% 95% 92%

Check restaurant
hours 22% 46% 68% 58% 45% 39% 43%

Get directions 56% 70% 93% 81% 62% 66% 71%

Overall SUM 53% 68% 88%
a After entering data for each participant and each task, these are the standardized scores calculated by SUM, including an overall SUM score
and a confidence interval for it.

Table 8.8 Sample standardized data from a usability test a .
a After entering data for each participant and each task, these are the standardized scores calculated by SUM, including an overall SUM score and
a confidence interval for it.

The online tool also provides the option to graph task data from a usabil-
ity study, including the SUM scores. Figure 8.2 shows a sample graph from
the tool.

Figure 8.2 Sample graph of SUM scores from http://www.usabilityscorecard.com/ . The tasks of this
usability test are listed down the left. For each task, the orange circle shows the mean SUM score and
bars show the 90% confidence interval for each. In this example, it's apparent that the “Reconcile
Accounts” and “Manage Cash-Flow” tasks are the most problematic.

8.2 USABILITY SCORECARDS
An alternative to combining different metrics to derive an overall usability score
is to present the results of the metrics graphically in a summary chart. This type
of chart is often called a Usability Scorecard. The goal is to present data from