Concern about the size and cost of Medicare is understandable. With 10,000 or so baby boomers due to reach age 65 every day for the next 18 years, Medicare enrollment is exploding, and based on our projections, by 2023 — 10 years from now — should reach 66 million, up from 50.3. The need to find better ways to deliver quality health care to seniors at a reasonable cost is obvious. What’s interesting is that an effective way to do this already exists: the Medicare Advantage program, which some in Washington are seeking to curtail (Daniel Gorlin and John Kaplan, 7/2).