You have to be a little careful to make sure that the conditions of the study are matching your conditions. As an example the TDD study you mentioned compared

You have to be a little careful to make sure that the conditions of the study are matching your conditions. As an example the TDD study you mentioned compared the defect rates of a new software developed once with TDD and once with Code Review. At work we do TDD mostly to help us developing (faster feedback if the code does what i want, running it on the target needs 10+min), to have an example how the code should be used and to now that a refactoring broke something unrelated. If it helps us with a refactoring or reduces the defect reduction rate that is a nice benefit but not the main reason why we use TDD. So it depends on what you do if a study is applicable or not.