Menu Interfaces Benefits of menu’s: Learnability, memorability, error avoidance Minimize memory load Drawbacks: possible inefficiency hierarchical complexity (menu trees)

Menu Interfaces – Design Issues and Choices What kind of menu? 1-level v. hierarchical v. “linear” Affordance of menu: how to activate/deactivate pull down, pop-up, dropdown list always present: list, toolbar, toolbox, radio buttons appears automatically

1-level Pull-down Menu

2-level Hierarchical Menu

Select Database 1.Employee database 2.Customer database 3.Product database 4.Sales database >> 1 Type number of desired selection and Old-style linear menu system

Select Function 1.Add a records 2.Delete records 3.Print report >> 3 Type number of desired selection and

Select Report Style 1.Print selected records 2.Print statistics 3.Print selected records and statistics >> Type number of desired selection and

Menu Design Issues and Choices (cont.) Number of items items per menu = “breadth” Number of active choices Menu title names Menu item names Menu item ordering

Menu Design Issues and Choices (cont.) Appearance text v. iconic items v. both horizontal v. vertical v “fast and vast” Idioms: selection listcheck box menu barradio buttons drop-down selection listtoolbars push buttons/hyperlinks pie menus Q. Are embedded links menu’s ?? list A. Only if they are arranged in a list

Menu Design Issues and Choices(cont.) Item Selection mechanism (affordance) by: Mouse click Drag and release (Macintosh) Keyboard entry - arrow cursors & - Mnemonic letters & - Other “shortcuts” Affordance for Hierarchical Menu selection: MouseDown Mouse-over with pop-up levels (use of DELAYS)

Efficiency of Menu’s Response Time and Display Rate The speed at which a user can move through menus may determine their attractiveness as an interface mechanism. User performance and preference favors broader, shallower menus

Efficiency of Menu’s (cont.) Menu shortcuts: Alt-key opens menu CTL or function key activates menu item Menus with typeahead recommended when: Menus are familiar Response time/display rates are slow BLT approach: single-letter menus with typeahead leads to concatenation of hierarchical menu selections into mnemonics. Menu names or bookmarks/macros for direct access

Hierarchical Menus Design Issues Taxonomy design problem Male, female Animal, vegetable, mineral Fonts, size, style, spacing Depth versus Breadth - difficult trade-off

Depth v. Breadth Trade-off in Menu Design Kiger (1984) grouped 64 menu items 6 ways: 8, 8 | 4, 4, 4 | 2, 2, 2, 2, 2, 2 | 4, 16 | 16, 4 22 subjects performed 16 searches. Rated for speed, accuracy, preference. 2 X 6 was worst in all categories, 8 X 8 rated highly

Models of Menu Performance Time for one selection: T = k + c * log 2 b (b is breadth; k,c parameters representing scan and selection time) Total time = D * T where D is depth of tree = log b N Hierarchical Menus

Models of Menu Performance (cont.) Experiment with 4096 items: 16 per menu twice as fast as 2 per menu Hierarchical Menus Example 1: N = 4096, b = 16, D = 3 Predicted time for a search is 3 * (k + c * 4) or [3k + 12c] Example 2: N = 4096, b = 4, D = 6 Predicted time for a search is 6 * (k + c * 2) or [6k + 12c] c is time to visually search, k is mechanical overhead of moving the mouse, clicking, etc.

Menu Design Guidelines Task-related Grouping Create groups of logically similar items Form groups that cover all possibilities Make sure that items are non-overlapping Use familiar terminology, but ensure that items are distinct from one another

Menu Design Guidelines (cont.) Ordering Menu Items The order of items in the menu is important, and should take natural sequence into account when possible: Time Numeric ordering Physical properties When cases have no task-related orderings, the designer must choose from such possibilities as: Alphabetic sequence of terms Grouping of related items Most frequently used items first Most important items first Use horizontal bars to create within-menu grouping

Menu Design Guidelines (cont.) Naming of Menu Items Titles - For single menus, use a simple descriptive title. For linear menus, use the exact same words in the higher-level menu items as in the titles for the next lower-level menu. E.g. if a menu item is called Business and Financial Services, the next screen should have that phrase as its title. Phrasing of menu items Use familiar and consistent terminology Ensure that items are distinct from one another Use consistent and concise phrasing Bring the keyword to the left

Menu Interfaces - Summary of Design Issues Choose type of menus (simple, linear, tree structured) Choose menu selection mechanism ( & shortcuts) Grouping/organizing menu items Taxonomy design for tree-structured menus Depth v. breadth trade-off Select names of menu choices Order choices within each menu Select menu titles