As we have seen in the previous section, specific dialog situations (like those obtained with the hierarchical clustering) proved to be more efficient than the semantic channel (represented by the calltype labels) for clustering utterances in relation with the language used, at least from the perplexity point of view.
for clustering dialogs rather than utterances, the semantic channel is the main channel that we are going to use because in this case we want to characterize the whole interaction between a system and a user rather than just the language used.