Investigating the impact of peer code review and pair programming on test-driven development

Pair programming and peer code review are two collaborative inspection methods that improve the quality of software. These light-weight review techniques are low-cost alternatives to formal inspections and rigorous reviews that commonly remove 90% of software defects before even the first test case is run. While pair programming has many advocates, evidence suggests that pair programming is not as useful as claimed and the requirement of the pairs to co-locate is hindrance on many development projects. Peer code reviews, however, have been shown to be just as effective as pair programming and are a better fit for many of today's software efforts that are being developed collaboratively, but asynchronously, in the cloud. In this paper we demonstrate peer review's effectiveness as compared to pair programming in the context of Test Driven Development (TDD), a popular agile programming technique that's rapidly gaining mainstream acceptance. The empirical evidence also shows that equal quality programs can be produced at a lower cost (28% less than pair programming) using a peer review technique in TDD as compared with traditional pair programming.