The Added Usefulness of Process Measures Over Performance Measures in Interface Design

Various studies concerning the application of usability evaluation methods have shown the usefulness of these testing methods. The objective of this study was to evaluate the added advantage of collecting process measures (data used to learn how and why an error occurred) over performance measures (data used to determine what went wrong) in interface design. The most salient finding of this study is that when used in the design/redesign process, performance data improved effectiveness (i.e., reduced the number of errors), whereas process measures data improved efficiency by reducing the time needed to complete tasks. The results from this study, as with any other usability study, should be of particular interest to the software industry, which is constantly trying to reduce development time and resources while improving user-friendly interface design.