For two decades, software inspections have proven effective for
detecting defects in software. We have reviewed the different ways
software inspections are done, created a taxonomy of inspection methods,
and examined claims about the cost-effectiveness of different methods.
We detect a disturbing pattern in the evaluation of inspection
methods. Although there is universal agreement on the effectiveness of
software inspection, their economics are uncertain. Our examination of
several empirical studies leads us to conclude that the benefits of
inspections are often overstated and the costs (especially for large
software developments) are understated. Furthermore, some of the most
influential studies establishing these costs and benefits are 20 years old
now, which leads us to question their relevance to today's software
development processes.
Extensive work is needed to determine exactly how, why, and when
software inspections work, and whether some defect detection techniques
might be more cost-effective than others. In this article we ask some
questions about measuring effectiveness of software inspections and
determining how much they really cost when their effect on the rest of the
development process is considered. Finding answers to these questions will
enable us to improve the efficiency of software development.
(Also cross-referenced as UMIACS-TR-95-104