LAYOUT APPROPRIATENESS - A METRIC FOR EVALUATING USER-INTERFACE WIDGET LAYOUT

Numerous methods to evaluate user interfaces have been investigated. T hese methods vary greatly in the attention paid to the users' tasks. S ome methods require detailed task descriptions while others are task-i ndependent. Unfortunately, collecting detailed task information can be difficult. On the other hand, task-independent methods cannot evaluat e a design for the tasks users actually perform. The goal of this rese arch is to develop a metric, which incorporates simple task descriptio ns, that can assist designers in organizing widgets in the user interf ace. Simple task descriptions provide some of the benefits, without th e difficulties, of performing a detailed task analysis. The metric, La yout 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 exi sting system or from a simplified task analysis. The appropriateness o f 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 frequ ent methods in the design. In addition to providing a comparison of pr oposed or existing layouts, an LA-optimal layout can be presented to t he designer. The designer can compare the LA-optimal and existing layo uts or start with the LA-optimal layout and modify it to take addition al factors into consideration. Software engineers who occasionally fac e interface design problems and user interface designers can benefit f rom the explicit focus on the users' tasks that LA incorporates into a utomated user interface evaluation.