To be clear I am not arguing that tools and practices like TDD, microservices, ai assistants, and so on have no effect. They almost certainly have an effect (good or bad).

It’s just the unfortunate reality that quantitatively measuring these effects in a meaningful way seems to basically be impossible (or at least I’ve never see it done). With enough resources I can’t think of any reason it shouldn’t be possible, but apparently those resources are not available because there are no good studies on these topics.

Thus my skepticism of the “studies” referenced earlier in the thread.