Are the Perspectives Really Different? – Further Experimentation on Scenario-Based Reading of Requirements

Perspective-BasedReading (PBR) is a scenario-based inspection technique whereseveral reviewers read a document from different perspectives(e.g. user, designer, tester). The reading is made accordingto a special scenario, specific for each perspective. The basicassumption behind PBR is that the perspectives find differentdefects and a combination of several perspectives detects moredefects compared to the same amount of reading with a singleperspective. This paper presents a study which analyses the differencesin perspectives. The study is a partial replication of previousstudies. It is conducted in an academic environment using graduatestudents as subjects. Each perspective applies a specific modellingtechnique: use case modelling for the user perspective, equivalencepartitioning for the tester perspective and structured analysisfor the design perspective. A total of 30 subjects were dividedinto 3 groups, giving 10 subjects per perspective. The analysisresults show that (1) there is no significant difference amongthe three perspectives in terms of defect detection rate andnumber of defects found per hour, (2) there is no significantdifference in the defect coverage of the three perspectives,and (3) a simulation study shows that 30 subjects is enough todetect relatively small perspective differences with the chosenstatistical test. The results suggest that a combination of multipleperspectives may not give higher coverage of the defects comparedto single-perspective reading, but further studies are neededto increase the understanding of perspective difference.