Figure 4

Distribution of topics amongst DBHT clusters. The cluster label k versus the number of indicators in each cluster \(N_{k}\). Each bar is divided into the number of indicators in cluster k which belong to each topic, with each colour corresponding to each topic according to the key on the right. The arrows with the orange asterisks point to clusters (starting from the left) 6, 8, 18, 20, 34, 49, 72, 73, which are used in Fig. 5 and Fig. 6