Suppose you’re an eye doctor and you’re treating a patient with macular degeneration, a disease that can cause blindness. You have the choice of giving one of two drugs — one that costs $2,000 per treatment and another, very similar one, which costs $50 per treatment.

Do you think it would influence your decision if you were paid $117 more if you chose the more expensive drug?

That, essentially, is the system we have now. For doctors who give drugs in their offices, mostly cancer, eye and arthritis specialists, Medicare asks them to buy the drugs themselves and then pays them back when they give the drugs to patients. Currently, Medicare pays doctors the average sales price of the drug, and then tacks on a 6 percent bonus to cover their administrative costs. Obviously, 6 percent of $2,000 is a lot more than 6 percent of $50.

Doctors argue that they choose drugs based on what’s most medically appropriate for their patients — and most probably do. (There are some good reasons a doctor might choose the $2,000 drug over the $50 drug for some patients.) But several analysts have looked at this policy and determined that it creates the wrong kind of incentives for doctors — encouraging them to choose pricier treatments even if they are no better than cheap ones.