The problem with most research supporting the use of TDD is that it compares TDD with a base line of no unit testing at all, without controlling for adding unit tests either first or last but without the test-
driven aspects.
There seems to be a fairly strong case for adopting unit tests in typical commercial development processes, and some interesting debate regarding whether it is more effective by various metrics to write the tests before or after the development, but there isn't much evidence that I've seen for going the extra way to a fully test-driven process.