Importance dendrogram showing the most informative multifactor trends in change in average condition score (BCI_ave). The change in condition of the bridges between two consecutive PIs has been banded from best to worst by using an even split into five bandings with the same number of bridges in each. Each pie chart represents the distribution of the condition change bandings within the subpopulation below that point in the tree structure. The top ‘All’ pie chart represents the distribution of change in condition in the full population of bridges for which direct comparisons could be made. The red text on each branch of the tree represents the attribute that the data set has been partitioned by at that level, and the black text represents the value of the attribute