SOVO: Usability Questionnaire for Voice-Only User Interfaces

This article presents the creation and validation of the SOVO instrument, which measures perceived usability by users. To achieve this, we conducted a three-stage instrument study. Twenty out of 160 items from nine questionnaires used to assess usability in VUI (Voice User Interfaces) were selected. The researchers established factors and the type of response. Expert judges supported the application of CVC, and after two rounds, the instrument had 15 items, with eight items rated as good and seven as excellent. Next, we administered the SOVO instrument to a sample of 314 users and conducted a statistical analysis, which validated the instrument. We found that the items demonstrate high internal consistency, with an alpha of 0.96 and a lambda-6 of 0.97. Finally, we performed an exploratory factor analysis, identifying three factors: Likeability, Intelligibility, and Usability. It is important to have reliable instruments since it is very common to see VUI in a wide range of the users activities.