For years, private Medicare Advantage plans have enjoyed generous payments from the government, currently averaging 9 percent more than the cost of care in traditional Medicare. The government's benevolence enabled Medicare Advantage plans to offer lower out-of-pocket costs and extra insurance benefits compared with traditional Medicare - like dental, vision, and prescription drug coverage. About 11 million seniors are signed up, nearly one-fourth of Medicare recipients.

That's about to change under the health care overhaul. Payments are being trimmed back starting next year for all plans, to correct what Obama says is wasteful overspending. However, beginning in 2012, the law directs Medicare to award bonuses to high performing plans - plans that score four stars or better on a 5-star rating system. The payment shift means that high-quality plans will find it a lot easier to keep offering extra benefits, while others will struggle. Indeed, Medicare's own analysts predict an exodus from Medicare Advantage back to the traditional program after the cutbacks begin.

The government's rating system evaluates health plans according to several measures, including customer service, prevention and medical care for people with chronic health problems. The ratings, already available on medicare.gov, assign one to five stars for quality, with one signifying poor performance and five excellent.

How the private plans score on the quality rating system set up by the government is about to have a direct impact on insurers' finances -- not to mention seniors' benefits and premiums. President Barack Obama's health care law ties what the plans get paid by the government to the quality they provide, for the first time. These ratings are about to become much more important. When you start linking quality to payment, you can bet the plans are going to be very motivated to bring the scores up.

Millions of seniors signed up for popular Medicare Advantage insurance plans don't get the best quality, an independent study found. There seems to be plenty of room for improvement. The study being released in April 2010 by looked at the health plans that seniors pick, according to the plans' scores on a government rating system designed for consumers. Overall, senior have proven to be poor shoppers of Medicare Advantage plans. The analysis found that 47 percent of Medicare beneficiaries are in plans that rate three stars or two -- medium to fair quality. Just 23 percent were signed up in plans that rate four or five stars -- very good to excellent quality. Many of the rest were in plans not yet rated.

If the new system of rewarding the best plans and culling out the poor performers works, seniors will be more likely to be gravitate to the better plans.