Key Tips for User-Centered Design (continued)

Make tasks physical with direct manipulation.

Where possible, simplify tasks by letting users physically control the system. This sidesteps training that may be needed for more abstract commands or functions.

Don't use direct manipulation if physical action or concepts become difficult.

Avoid making users work extra hard! For example, don't force users to drag 6 stick figures when they could type "6" faster and more easily.

Check the physical work for drag-and-drop.

Insure that your design provides shortcuts for drag-and-drop such as select-to-delete or group-and-drag. Avoid dreary, time consuming drag-and-drop situations like dragging a fax address from one list to the send list. For example, if only one send list exists, then, point-and-click is faster than drag-and-drop! If multiple destinations exist, then drag-and-drop may be best.

Store data by spatial position.

Users remember best when associations are made with a familiar location (cf., "Method of Loci" as a memorization technique.) For example, position OK and Cancel buttons and menu bar options consistently. This capitalizes on the user's natural skill in spatial recall of often-used items.

Avoid "sterile" or "featureless" spaces.

A blank file folder doesn't aid spatial memory very much. For example, give users an on-screen office to help locate a file, document, or application module. A structure such as the "Controlled Task Panel" helps the user perceive relationships between objects. (See our GUI design column on menus.)

Use presentation graphics.

Meet the needs of users who must quickly find trends, patterns or relationships in their data. Charts show these better than tables.

Don't clutter the screen.

For example, avoid 3-D charts when two dimensions are enough to describe the data. (In other words, don't be misled by 3-D advertising claims made by charting programs.)

Don't mislead users.

Keep x and y axis measurement scales authentic. Avoid broken scales. Maintain a constant aspect ratio between the x and y axes. Don't allow "rubber band" changes in aspect ratio.