Section 7 Cluster analysis of topic co-occurence

The topics were grouped into four more general perspectives on the vaccination issue based on a cluster analysis of their co-occurrences in the posts. Hellinger distance was used as distance measure and Ward’s algorithm as agglomeration method. The cluster solution with four groups was deemed most sensible. topic_cluster.R in the OSF repository documents the cluster analysis and Figure 7.1 reports the dendrogram of the cluster analysis.

Figure 7.1: Dendrogram of the cluster analysis

The grey box groups the topics in the general vaccination debate perspective. The orange box groups the topics in the specific vaccinations perspective. The blue box groups the topics in the practical issues perspective. The red box groups the issues in the relationship and communication perspective. Note that the topic on tick-borne encephalitis (TBE) was reassigned from the practical issues perspective to the specific vaccinations perspective based on topical considerations.