[pithymaxim]

Checklists are probably good but looking at the actual paper[0] I don't think we can conclude "a third" with much confidence. The mortality rate for surgeries was already declining--the argument is that it declined faster during the implementation period (Fig 2; 2008-2010). Also it appears the types of admissions changed a lot during the same period based on the stark difference between Fig 1 (unadjusted) and Fig 2 (adjusted).

I'm surprised that the researchers didn't use better data or variation (e.g., hospital-level mortality or the timing of the rollout) to strengthen the case. So much can be lurking beneath annual country averages...

[0]: https://onlinelibrary.wiley.com/doi/full/10.1002/bjs.11151