TDD Adoption Numbers

Matt Hawley posted a few numbers in order to justify/support the adoption of TDD.

I've found an interesting research paper on the subject, from Matthias Müller and Frank Padberg from the Karlsruhe University in Germany.

Some of my personal views on the subject are:

  • I do find there's a slight overhead to developing Test-First. However all developers unit-test their code, to one degree or another. All developers write some form of test code. I believe the overhead comes, not from writing test code, but from using a testing framework.
  • IMO one of the greatest benefits I've experienced by coding test-first is that the code I write is testable (i.e. If someone else needs to write/extend test-code, for instance to test some wierd situation, it can easily be done);
  • Coding flows with much more confidence (more immediate feedback on what's wrong);

I do believe that TDD is a very helpful practice and from my experience, together with other practices like Refactoring, I do believe that it helps to write better code.