Tree testing has been attempted, but it is not clear how the results from tree testing informed the organization of the navigation.
Tree testing revealed insights about users' ability to find information within a structure tested, and showed what changes were made in order to address any problems identified.
Tree testing proceeded in multiple rounds, with adaptations made as necessary. Clear connections were made between the results of evaluation rounds and the design of navigation.
Tree testing was approached in targeted ways based on the project, with the method refined to match the needs and context of the work. No doubt is left about why this work was done or what value it provided in informing the quality of the design.