... the 47th Annual Meeting of the ACL and the 4th IJCNLP of the AFNLP, pages 879–887,Suntec, Singapore, 2-7 August 2009.c2009 ACL and AFNLP Comparing Objective and Subjective Measures of Usabilityin ... cor-related with each other: the correlation betweenlength and turns was 0.38; between length and re-sponse time 0.47; and between turns and responsetime 0.19 (all p < 0.0001).Dialogue quality ... performancedimensions of task success, dialogue quality, and dialogue efficiency, and has been applied to a widerange of systems (e.g., Walker et al., 2000; Litman and Pan, 2002; M¨oller et al., 2008). If...