An Empirical Study on Design Quality Improvement from Best-Practice Inspection and Pair Programming

The quality of the software design often has a major impact on the quality of the final product and the effort for development and evolution. A number of quality assurance (QA) approaches for inspection of early-life-cycle documents have been empirically evaluated. An implicit assumption of these studies was: an investment into early defect detection and removal saves higher rework cost. The concept of pair programming combines software construction with implicit QA in the development team. For planning QA activities, an important research question is how effective inspectors can be expected to be at detecting defects in software (design and code) documents compared to programmers who find defects as by-product of their usual construction activities. In this paper we present an initial empirical study that compares the defect detection effectiveness of a best-practice inspection technique with defect detection as by-product of constructive software evolution tasks during pair programming. Surprisingly, in the study context pair programmers were more effective to find defects in design documents than inspectors. However, when building a larger team for defect detection, a mix of inspection and pair programming can be expected to work better than any single technique.