Being able to take a TDD approach usually requires an idea of how to build testable code. Hell in some cases one might not have any idea what the code looks like at all, so testing it isn't possible.
At that point it just seems like an afterthought, and untestable code is one of the easiest ways to get some cheap tech debt.
Now getting around that sort of barrier is pretty hard since it requires more experience and discipline.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.