There are plenty of professions where it makes sense someone unpleasant still has a job because they're actually hyper competent (like software development) but why would physicians be filtered out of the profession for poor bedside manner? In what part of the world is there a surplus of supply of doctors that would allow for that?

I think you missed a bit of nuance. Psychologically, people are more likely to pursue a malpractice case against an incompetent physician who has poor bedside manner rather than an incompetent physician who has excellent bedside manner. So that specific quadrant would be penalized the most.

or doctors with bad bedside manner could move into non-patient-facing roles like research or pathology

TIL that there's a name for it. I always just sort of intuited this phenomenon.

"In the overall population, bedside manner and medical aptitude are likely uncorrelated."

I'd [citation needed] on that, depending on the condition.

In that for some conditions, successful diagnosis and treatment across a wide range of the population (not just the most educated, articulate, mentally with-it and compliant quartile) is going to depend on being able to get qualitative information from the patient, and interpret that correctly.

Equally though the medical profession has enough specialisation in terms of role to be able to put the right personality types in the right jobs.

citation: i made it up based on my intuition because this is a thought experiment to illustrate a paradox.

also "bedside manner" is not just about conveying information. that would be a big part of successful treatment.

if you ask people about bedside manner is all going to be about personality and emotional sensitivity (where they gruff? did they make you feel bad? etc). somebody can be amazing at conveying accurate information but come across as a complete asshole, and those are the 'bad bedside manner' docs.

I think this application of Berkson's paradox is misleading. A physician can be expected to have a high medical aptitude because of training, not filtering. Medical degrees are not withheld from people with low medical aptitude and given to people with high medical aptitude, people are trained then filtered.

> So if you find a doctor with bad bedside manner, they're likely to have better medical aptitude otherwise they would've been filtered out.

I propose the opposite, a doctor with bad bedside manner likely has lower medical aptitude. I believe there is training for doctors to improve their bedside manner. Then "trainability" may be a latent factor which correlates the quality of a doctor's bedside manner and medical aptitude.