Australian Scrum Community

A paper is available from Microsoft Research titled “Evaluating the Efficacy of Test-Driven Development: Industrial Case Studies”. It takes a look at two Microsoft projects and reports on the effort involved in writing tests versus the reduction in defects. Interesting stuff.

Project A
A C++ networking library. Test-Driven Development (TDD) required 25-35% of additional effort, resulting in a defect density of 2.6x less than that of an equivalent project not using TDD. The team was highly experienced in the domain and language used.

Project B
A C# web services product. TDD required 15% of additional effort, resulting in a defect density of 4.2x less than that of an equivalent project not using TDD. The team was had medium experience in the domain and language used.

The paper states drawing conclusion from these figures is difficult because there are a large number of context variables in software development. e.g. Team experience, team size, management experience, language, product type, etc.

Via Steve: Developing on the Edge.