3.2. Usability Evaluation
Initial Usability Testing: A total of 17 participants completed the initial scenario-based usability test. The mean task completion rate exceeded 95%. The most frequently missing steps were playing and stopping the tutorial videos (four out of these five participants). The analysis of the think-aloud data during testing showed that most participants felt the app was easy to use (Usability Survey: Twelve app group participants completed the usability survey at the post-test. Overall, the app showed good usability with a mean SUS score of 78.13 (see Posttest Survey: The 12 app group participants who completed the post-test surveys also shared brief open-ended comments with us about how the app was helpful. A majority of participants (10, 77%) commented that the app helped them practice the VFE and improved their vocal function or voice quality. However, one participant preferred in-person sessions over using the VFE app and two participants did not leave comments.Focus group: Six app group participants joined a focus group to provide further information about their experiences. The three primary locations of app use were their homes, cars (especially at the parking lot), and restaurants. The majority followed the recommendation to conduct their daily VFE sessions once in the morning and the other in the evening. However, some completed VFE sessions during their lunch break. Several improvement ideas were identified. The top five were: (1) adding a clear indication for exercise competition; (2) adding a customizable reminder and snoozing function; and (3) showing their best VFE records on top. These improvement ideas were consistent with weaknesses identified in the usability surveys about customization and interactivity. The new version of the app has addressed these issues.