Someone pointed me at this video today. Pretty interesting stuff…
Channel 9 talks with Nachi Nagappan about Test Driven Development (TDD): Does it work better? How better? What’s the catch? To answer these questions, Nachi talks about a study done over multiple teams within and outside of Microsoft on TDD. The results are very interesting, as they are based on real teams with real products. Watch the video or download the paper to grok the numbers in details.
The paper has some pretty interesting results based on three studies (from the abstract).
The results of the case studies indicate that the pre-release defect density of the four products decreased between 40% and 90% relative to similar projects that did not use the TDD practice. Subjectively, the teams experienced a 15–35% increase in initial development time after adopting TDD.
Although development time increased defect rates decreased very significantly.
You can find this and other videos on the patterns & practices Agile Showcase.