Comparison of Telephone Menu Interfaces

Performance Times

It was expected that the performance times for Shoutmail would be quicker than Coolemail. The experiment however showed no statistically significant differences between the two systems. Shoutmail had an overall average time which was 16 seconds faster than Coolemail. The main reason was that Coolemail played a short commercial clip before the user was able to access the Inbox. This clip added valuable time to the Coolemail performance, but some was gained with Coolemail’s short and quick menu system. Coolemail users only have to traverse two levels to hear an email, while Shoutmail requires three.

User Satisfaction

Shoutmail used a faster computerized voice to read the emails than Coolemail. The female group gave Coolemail a much higher preference when it comes to rating the speed of the system (5.44 compared to 5.22, out of 9) while the male subjects gave Shoutmail a small preference (5.18 compared to 5.00, out of 9). The subjective rating of the speed of the systems was probably affected by personal preference, since it gave no clear indication of what the users believed to be faster. 

Interestingly enough, the subjects seemed to prefer Shoutmail to Coolemail when it comes to rating how much of the message they understood. Even with Shoutmail’s noticeably faster computerized voice, the subjects seemed to understand more than Coolemail’s reading. One reason might be that Shoutmail uses a female computerized voice, while Coolemail uses a male version. The synthesized voice engine for both systems is the same, meaning they read the messages almost identically, with the same tone and grammar. As stated earlier, if the intelligibility of naturalness is low, then acceptability is not likely to be very high. The female voice in Shoutmail might be more natural to the subjects than Coolemail’s male voice.

Department of Computer Science: Direct questions and comments to the student editorial team