(a) do research, publish papers, test thoroughly new treatments in well defined trials and slowly build up a biological theory as well as official guidelines and treatments. And
(b): measure the outcomes of different hospitals, declare the best performer's methods as the state of the art and expand these methods elsewhere. If the measurement is sound, one can argue that they are both evidence based. The former is slow but may provide a deeper understanding of the inner workings of the deaease. The latter is fast but it's hard to tell exactly why it works so well.
The was a shift in machine learning research in recent years.
(a): write theoretical papers and study using math the generalization performance of algorithms.
(b) release a new challenging dataset every year (except a test set) and organize a prediction competition on this dataset. The winner algorithm is declared the state of the art, and can be applied to other datasets, event though Boone understands why it works so well.
The approach (b) was particularly fruitful and efficient in recent years. Let's hope that applying this approach to medicine Will lead to great outcomes!