Since I wrote that article I've found one or two papers about the subject, one of them was one that I heard about in .Net Rocks, it compared code reviews with unit testing, but I can't find it :S While I was searching I found this one from NCSU and Microsoft: "On the Effectiveness of Unit Test Automation at Microsoft": http://collaboration.csc.ncsu.edu/laurie/Papers/Unit_testing... It's not about TDD although they mention it in the paper. I'll try to find that one about code reviews and post it here as well