Figure 2 shows the discrepancy between the dialogue efficiency in Phase 1 (HCI) versus Phase 2 2 The shortest dialogues were 3:18 (E) and 3:30 (G) and the longest 12:05 (E) and 10:08 (G).
the usability of such conversational dialogue systems is still unsatisfactory, as shown in usability experiments with real users (Beringer, 2003) that employed the PROMISE evaluation framework described in Beringer et al.