Another thing to take into account is who's coding, what they're coding in, what they're building, how big their team is, how mature the team is (i.e. how long

Another thing to take into account is who's coding, what they're coding in, what they're building, how big their team is, how mature the team is (i.e. how long have they been working together) and how their environment's set up. As with most questions, context is everything, so should anyone experiment to find the best solution you'd want them to include those details in their conclusions, and ideally to alter and test against each of those variables and show the effects of BDD/TDD under those conditions.