Automatic Summarization of Online Debates
Table 2: Average silhouette scores derived from the term-based clustering approach
['[BOLD] Number of Clusters', '[BOLD] Average Silhouette Score']
Silhouette evaluates the clustering performance by determining the appropriateness of documents assigned to a cluster rather than the other clusters. These documents are represented as coordinates. Silhouette calculates the pairwise difference in both inter-cluster and intra-cluster distance. As shown in the table, the system generated 39 clusters based on the climate change terms annotated by the ClimaPinion service. The interpretation based on the score is the data points are assigned nearly to the decision boundaries of the clusters. Especially, when salient sentences contain multiple climate change topics, clear clustering boundaries are difficult to achieve. This circumstance indicates that such a simple clustering approach is less applicable for grouping semantically similar sentences together and that the task asks for more sophisticated ways for achieving a better performance.