# Creation, Analysis and Evaluation of AnnoMI, a Dataset of Expert-Annotated Counselling Dialogues +
## 6 Dataset Analysis
### (Main) Behaviour and Talk Type as Conversation Proceeds  
Following [13], we divide each conversation into 5 parts: \([0.0,0.2]\), \((0.2,0.4]\), \((0.4,0.6]\), \((0.6,0.8]\) and \((0.8,1.0]\), in order to probe conversational properties at different dialogue stages. Specifically, we examine the distributions of different therapist behaviours and client talk types at these stages.  
Among the trends shown in Figure 5, one can observe in both high- and low-quality MI that the proportion of Question gradually decreases as the therapist gathers more  
Figure 4: Distribution of next-turn therapist behaviours given different client talk types in the current turn.  
Figure 3: Distribution of next-turn client talk types given different therapist behaviours in the current turn.  
information about the client from the progressing conversation. The amount of Reflection, on the other hand, generally fluctuates within a small interval throughout a dialogue in both high- (27-31%) and low-quality MI (2-8%), which means that Reflection is common throughout a high-quality MI session and rare throughout a low-quality one. Finally, the proportion of Input rises during the middle stages (\((0.4,0.8]\)) in both high- and low-quality MI, but the increase is substantially more pronounced in low-quality MI sessions (from \(\sim\)30% to \(\sim\)60%) than in high-quality ones (from \(\sim\)10% to \(\sim\)15%), which further indicates that a non-adherent therapist tends to talk from their own perspective more as the conversation develops.  
The trends of different client talk types are displayed in Figure 6. A clear shift is shown in high-quality MI: there are similar amounts of Change Talk and Sustain Talk at the beginning of a conversation, but Change Talk becomes more present steadily and eventually reaches around 40% at the end of a dialogue, while the share of Sustain Talk diminishes gradually at the same time and drops to around 7%. In other words, the desired effects of MI-adherent therapy, namely change talk evocation and sustain talk reduction, become increasingly prominent with the progression of a session. In low-quality MI, however, during the early and middle conversation stages (i.e., \([0.0,0.6]\)), the proportion of Sustain Talk soars from approximately 10% to a little over 40%, while the number for Change Talk remains under 10%. Interestingly, the later stages (i.e., \((0.6,1.0]\)) show the opposite trend, as the growing share of Change Talk surpasses the declining proportion of Sustain Talk, finishing at around 30% and 12%, respectively, at the end. Nevertheless, the absolute %[Change Talk]-%[Sustain Talk] difference is clearly larger at the end of a high-quality MI session in general.  
Figure 5: Proportions of therapist behaviours in different conversation stages in high- and low-quality MI. The marked data points are sample means, and the error bars around them are calculated using bootstrapping with a 95% confidence interval.  
Figure 6: Proportions of client talk types in different conversation stages in high- and low-quality MI. The marked data points are sample means, and the error bars around them are calculated using bootstrapping with a 95% confidence interval.