A study of out-of-turn interaction in menu-based, IVR, voicemail systems

We present the first user study of out-of-turn interaction inmenu-based, interactive voice-response systems. Out-of-turn interaction is atechnique which empowers the user (unable to respond to the current prompt) totake the conversational initiative by supplying information that is currentlyunsolicited, but expected later in the dialog. The technique permits the userto circumvent any flows of navigation hardwired into the design and navigatethe menus in a manner which reflects their model of the task. We conducted alaboratory experiment to measure the effect of the use of out-of-turninteraction on user performance and preference in a menu-based, voice interfaceto voicemail. Specifically, we compared two interfaces with the exact samehierarchical menu design: one with the capability of accepting out-of-turnutterances and one without this feature. The results indicate that out-of-turninteraction significantly reduces task completion time, improves usability, andis preferred to the baseline. This research studies an unexplored dimension ofthe design space for automated telephone services, namely the nature ofuser-addressable input (utterance) supplied (in-turn vs. out-of-turn), incontrast to more traditional dimensions such as input modality (touch-tone vs.text vs. voice) and style of interaction (menu-based vs. natural language).