Not to be argumentative, but there is very little research that I've found on software engineering methodology that is in any way convincing. If you've got a good source, I would be incredibly grateful if you shared it! This is one of those areas where I wonder if a PhD is in any way useful. One the one hand in industry you have a complete lack of rigorous controls to measure your effectiveness and on the other hand in academia there is no way to fund the kind of project that would give you decent data (if you could somehow even figure out a way to introduce rigorous controls). I've thought about this quite a bit, and I think you're better off on the industry side if you are really interested in pursuing that kind of thing. Would love to be proven wrong, though.
I don't think you're wrong, I've seen a few interesting papers that nibble around the edges, usually examining how bugs get introduced and when they are fixed. I mentioned the field as an example of where someone coming from industry would not have to catch up to someone whose knowledge of Turing machines was still very fresh.
You're right, no trials on methodology that resemble something like clinical trials. And of course the reason for that is it would be incredibly expensive to even run a reasonable pilot (two small teams head to head implementing a realistic system), and if any organization has actually gathered data, it would be the crown jewel of proprietary knowledge. Not something you would ever open source.
The only thing I can say is that an immature field is one with opportunities left. If you can figure out how to jump the hurdles you can make a huge impact.
