Numerous methods to evaluate user interfaces have been investigated.
These methods vary greatly in the attention paid to the users tasks.
Some methods require detailed task descriptions while others are task-independent. Unfortunately, collecting detailed task information can be difficult. On the other hand, task-independent methods cannot evaluate a design for the tasks users actually perform. The goal of this research is to develop a metric, which incorporates simple task descriptions, that can assist designers in organizing widgets in the user interface.
Simple task descriptions provide some of the benefits, without the difficulties, of performing a detailed task analysis. The metric, Layout Appropriateness (LA), requires a description of the sequences of widget-level actions users perform and how frequently each sequence is used.
This task description can either be from observations of an existing system or from a simplified task analysis. The appropriateness of a given layout is computed by weighting the cost of each sequence of actions by how frequently the sequence is performed. This emphasizes frequent methods of accomplishing tasks while incorporating less frequent methods in the design. Currently costs are based on the distance users must move the mouse. Other measures such as the number of eye fixations necessary to extract the relevant information or measure like the number of changes in direction may also prove useful, but must be validated before they are made available for use. In addition to providing an comparison of a proposed or existing layouts, an LA-optimal layout is presented to the designer. The designer can compare the LA-optimal and existing layouts or start with the LA-optimal layout and modify it to take additional factors into consideration.
Software engineers who occasionally face interface design problems and user interface designers can benefit from the explicit focus on the users tasks that LA incorporates into automated user interface evaluation. (Also cross-referenced as CAR-TR-603)