It originates with the CMS, Centers for Medicaid and Medicare, sets the codes and there’s a committee of doctors that assigns relative value units to different types of work (“RVU”s). It’s all very complicated and opaque.
The US has this crazy amalgamation of taxpayer funded healthcare and private insurance funded healthcare where the each entity is trying to exert maximum pressure to either minimize expenses or maximize income, and it’s in a constant state of flux.
Thinking about the amount of man hours that are wasted on this endeavor resulting from a desire to not simply provide everyone a simple taxpayer funded system is disheartening.