A Longitudinal Cohort Study on the Retainment of Test-Driven Development
This research addresses software engineering practices for novice developers, but the findings are incremental as they confirm mixed prior results on TDD's benefits.
The study investigated the effects of Test-Driven Development (TDD) on software quality and developer productivity, finding no statistically significant impact on these measures, but observed that TDD users wrote significantly more tests and retained the practice over five months.
Background: Test-Driven Development (TDD) is an agile software development practice, which is claimed to boost both external quality of software products and developers' productivity. Aims: We want to study (i) the TDD effects on the external quality of software products as well as the developers' productivity, and (ii) the retainment of TDD over a period of five months. Method: We conducted a (quantitative) longitudinal cohort study with 30 third year undergraduate students in Computer Science at the University of Bari in Italy. Results: The use of TDD has a statistically significant effect neither on the external quality of software products nor on the developers' productivity. However, we observed that participants using TDD produced significantly more tests than those applying a non-TDD development process and that the retainment of TDD is particularly noticeable in the amount of tests written. Conclusions: Our results should encourage software companies to adopt TDD because who practices TDD tends to write more tests---having more tests can come in handy when testing software systems or localizing faults---and it seems that novice developers retain TDD.