A good place to get started there is Epistemology and the Psychology of Human Judgment, summarized on LW by badger

Thanks, I'll try to find the relevant parts.

This suggests that the marginal bit of medicine--i.e. the piece that people don't consume, but would if it were cheaper or do consume but wouldn't if it were more expensive--doesn't have a net impact

I didn't want to get in too in depth into this discussion, because I don't actually disagree with the weak conclusion that a lot of people receive too much healthcare and that completely free healthcare is probably a bad idea. But Robin Hanson doesn't stop there, he concludes that the rest of medicine is a sham and the fact that other studies show otherwise is a scandal. As to why I don't buy this, the RAND experiment does not show that health outcomes do not improve. It shows that certain measured metrics do not show a statistically significant improvement on the whole population. In fact in the original paper, the risk of dying was decreased for the poor high risk group but not the entire population. Which brings up a more general problem - such a study is obviously going to be underpowered for any particular clinical question, and it isn't capable of detecting benefits that lie outside of those metrics.