Breadth versus Depth
One issue regarding menu design is known as the breadth versus depth trade-off. One alternative is to have only a few choices on every menu page and many, or at least more, levels in the menu hierarchy. This deep hierarchy results in many cascading menus. The other alternative would be to have more options on an individual menu page, thereby reducing the number of levels in the hierarchy, and increasing the breadth.
The question is which alternative is best? Research has shown that it is usually better to minimize depth at the expense of breadth. This means avoiding the use of cascading menus at the expense of long menu pages.
The optimum length of a menu page depends on three variables:
The following table shows the relation between these three variables and the optimum length of a menu page.
Relation between User/Task Variables and Optimum Number of Options
Use this table to determine the maximum optimal length of the menu pages in your application. Then use this length, as a starting point to determine how much depth is necessary to include all your menu options. In addition:
Each user group has its own menu structure. The maximum number of menu options per user group menu must not exceed 999. If you define more options, you may encounter unexpected system behavior.
The hierarchical menu system consists of menu pages that have a title plus a list of options (menu lines). Each menu option is a combination of:
The possibility of having a menu page contain other menu pages gives the menu system its hierarchical structure.