And I'm certain they are all correct. Ask an ER doctor what percentage of testing and diagnostics are to simply cover their backside. Invariably their answer will be between 1/3 and 2/3.

Why do you think in 2001 HALF of the world's MRIs were in the USA? Standard of Care, and if you didn't use that MRI to rule out some 1 in a 1,000 outlier condition you'd lose that claim in a heart beat.

I think 5% is too low, but overall it's not the ER amounts I mention above either. I'd bet in practice it would be something close to 20% overall healthcare expenditures.

But... in thinking a bit more, it is interesting to see the stupid things physicians do when they know they are covered by a State's sovereign immunity and liability is capped at $50,000.