When forced to choose between abstract evidence and experience, many physicians tend to rely on experience. This keeps health care costs high, write consultants Ngan MacDonald and Walter Linde-Zwirble in this opinion piece. MacDonald also discussed the piece on the Knowledge at Wharton show on Wharton Business Radio on SiriusXM channel 111. Listen to a clip above. A study of Blue Cross insurers released on July 9 by the plans’ trade association reported that health insurers are slowly moving toward “value-based” payments to doctors and hospitals. Instead of basing payments on the number of tests and procedures performed, they are experimenting with a system that rewards providers for improving care and lowering costs. The goal, says Blue Cross, is to move away from a system that rewards high cost over high-quality, efficient treatments. That laudable goal, however, is likely to encounter resistance in a place you might least expect it: The highly rational, scientifically trained minds of physicians.…