The ruling on self-referral is sure to infuriate critics. Studies suggest that when physicians invest in laboratories and X-ray centers, their patients receive more tests and pay higher prices. Last December, an AMA advisory council condemned self-referral as a conflict of interest and urged physicians to abstain. But the association’s policymaking House of Delegates ignored that advice last week, reasoning that if a doctor discloses his commercial interests, patients will weigh his advice accordingly.

To give those patients a tool, the AMA delegates calling on everyone in the industry–from doctors to hospitals, pharmacies and clinical labs–to “post the price of products and services.” AMA policies don’t have the force of law, but most doctors comply with them. And though no one is predicting a rash of illuminated sandwich boards touting discount tonsillectomies, the new rule could help discourage outrageous fees. As AMA spokesman Craig May observes, posting price lists will at least “put people in the habit of knowing what health care costs.”