Hierarchical Action Tree


Depending the complexity of the application, more or less commands will be available for interoperatation with the system. This patterns deals with the concern of arranging such command in an intelligible way to seek for usability, lowest learning curve, & ease of use.

HAT Sample 1
Figure 1. Typical Mac application menu.

HAT Sample 2
Figure 2. Adobe Macromedia web-site main menu.





Use a tree to structure your commands. The criteria to apply in the arrangement is open: logical grouping of functionality (e. g.application), alphabetically (e.g. thesaurus or index), based on user groups (e.g. web portals).

When the numbers of commands is big enough consider applying techniques like Card Sorting or other Information Architecture techniques to seek for a good design.


Arranging choices in a logical way easy to understand & discover for the users.


Menus in GUI applications (Figure 1) & web site navigation (Figure 2) are daily examples of this pattern. The tree helps to organize the options available.


A tree arranging the commands available. Items in the first level will be the most accessible ones, on the contrary, items in the lower levels will be difficult to reach to.

Root CUIP Metalevel

Valid XHTML 1.0 Strict Valid CSS