[mikenuman]

This is a very difficult area.

Firstly, these consults are never as easy or logical in real life. If you think doctors don't understand Bayesian probabilities then how well do you think patients do?

Decision making when screen positive results occur, with appropriate perspective, is virtually impossible for patients. I've lost count of the procedures I've done for incidental findings found with screening, which we KNOW are benign and will remain benign. Unfortunately, despite very strong reassurance, patients generally want these incidentalomas removed.

Secondly, unless your positive screening test can be dealt with.... a) by a procedure that has zero risk of complications and b) in a way where no stress is engendered while waiting for definitive results and) the costs of (screening + treatment) could not be more effectively spent elsewhere ...then there will ALWAYS be negative sequelae with screening. Therefore these negatives need to be assessed in a real world RCT of sufficient size and with maximal control of bias, to make sure they don't outweigh the positives.

Your perfect world of logical patients balancing pre- and post-test probabilities, and acting accordingly doesn't exist.