An external replication on the effects of test-driven development using a multi-site blind analysis approach

Davide Fucci, Giuseppe Scanniello, Simone Romano, Martin Shepperd, Boyce Sigweni, Fernando Uyaguari, Burak Turhan, Natalia Juristo, Markku Oivo

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

22 Citations (Scopus)


Context: Test-driven development (TDD) is an agile practice claimed to improve the quality of a software product, as well as the productivity of its developers. A previous study (i.e., baseline experiment) at the University of Oulu (Finland) compared TDD to a test-last development (TLD) approach through a randomized controlled trial. The results failed to support the claims. Goal: We want to validate the original study results by replicating it at the University of Basilicata (Italy), using a different design. Method: We replicated the baseline experiment, using a crossover design, with 21 graduate students. We kept the settings and context as close as possible to the baseline experiment. In order to limit researchers bias, we involved two other sites (UPM, Spain, and Brunel, UK) to conduct blind analysis of the data. Results: The Kruskal-Wallis tests did not show any significant difference between TDD and TLD in terms of testing effort (p-value = .27), external code quality (p-value = .82), and developers' productivity (p-value = .83). Nevertheless, our data revealed a difference based on the order in which TDD and TLD were applied, though no carry over effect. Conclusions: We verify the baseline study results, yet our results raises concerns regarding the selection of experimental objects, particularly with respect to their interaction with the order in which of treatments are applied. We recommend future studies to survey the tasks used in experiments evaluating TDD. Finally, to lower the cost of replication studies and reduce researchers' bias, we encourage other research groups to adopt similar multi-site blind analysis approach described in this paper.

Original languageEnglish
Title of host publication10th ACM/IEEE International Symposium on Empirical Software Engineering and Measurement, ESEM 2016
Subtitle of host publication8th-9th September 2016 Ciudad Real, SPAIN
EditorsAndreas Jedlitschka, Magne Jørgensen
Place of PublicationNew York NY USA
PublisherAssociation for Computing Machinery (ACM)
Number of pages10
ISBN (Electronic)9781450344272
Publication statusPublished - 2016
Externally publishedYes
EventInternational Symposium on Empirical Software Engineering and Measurement 2016 - Ciudad Real, Spain
Duration: 8 Sep 20169 Sep 2016
Conference number: 10th


ConferenceInternational Symposium on Empirical Software Engineering and Measurement 2016
Abbreviated titleESEM 2016
CityCiudad Real
Internet address


  • blind analysis
  • external experiment replication
  • test-driven development

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