Medicare Advantage is the private alternative to the traditional insurance program for seniors. It covers 11.7 million Americans. Some argue that it's less expensive than the public programs. Others say it's more expensive. It would be very hard for both of these things to be true. James Capretta and Yuval Levin made the case this week that Medicare Advantage plans are less expensive, citing an Aug. 1 study in the Journal of the American Medical Association. That research looks at what would happen if we implemented the Ryan-Wyden Medicare reforms (which are pretty similar to Romney's proposals) right away.