Effects of dialog initiative and multi-modal presentation strategies on large directory information access

This paper compares the effects of three different dialog initiative strategies (system initiative, mixed initiative and user initiative) on system performance and user acceptance on a large directory information access task. We used a personnel directory query application that could be accessed from a voice-only (telephony) and a multi-modal (kiosk) interface. Although the user initiative condition resulted in a lower proportion of in-grammar utterances, no significant effects of dialog initiative were observed for concept accuracy, perceived task completion, ease of use or user satisfaction. Dialogs were significantly shorter with the kiosk interface than with the telephony interface, and users preferred the kiosk interface and found it easier to use.