Perspective-Based Usability Inspection: Empirical Studies of Efficacy

Dr. Zhijun (William) Zhang
Department of Computer Science
University of Maryland, College Park

Friday, February 26, 1999
11 a.m.
Fuller Labs 311

Inspection is a fundamental means of achieving software usability. Past research showed that the current usability inspection techniques were rather ineffective. This research work developed perspective-based usability inspection, which divides the large variety of usability issues along different perspectives and focuses each inspection session on one perspective. It is hypothesized that 1) with focused attention and an appropriate inspection procedure for each perspective, each inspection session would detect significantly more usability anomalies covered by that perspective, and that 2) the combined results of different perspectives would uncover more anomalies than the combined results of the same number of inspectors using the same general inspection technique. Three experiments with human subjects were conducted to study the feasibility and effectiveness of perspective-based usability inspection by comparing it against a widely used technique, heuristic evaluation. The user interfaces being inspected were a Web-based data collection form (experiment I) and a commercial Web site (experiments II and III). The subjects included both professionals (experiments I and III) and students (experiment II), who worked either individually or in 2-person teams. The experimental results showed that on average each inspector using a perspective-based technique detected not only more anomalies related to the assigned perspective, but also more anomalies overall. For the combined effectiveness of multiple inspectors, perspective-based inspection showed a significant improvement over heuristic evaluation (30% for 3 inspectors in experiment I, 90% for 4 inspectors in experiment II, and 45% for 4 inspectors in experiment III). This work outlines a research agenda with some initial results, and provides implications for usability practice.

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Micha Hofri

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Carolina Ruiz

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Last modified: Sep 27, 2006, 16:05 EDT