More than 40 insurance companies have a contract to offer Medicare Advantage coverage. Once they have a Medicare contract, they will create different Medicare Advantage plans offered in different parts of the country. 

Every plan is unique – its costs, networks, customer service and more.

The uniqueness of each plan means a plan that is good for one person may or may not be good for another.

The most popular plans are sometimes the best

United Healthcare is the single largest provider of Medicare Advantage plans, closely followed by Humana and Anthem Blue Cross & Blue Shield.

In some parts of the country, like California and Colorado, Kaiser Permanente is a very large provider. In some areas, there are local plans with very good benefits, like Essence Advantage (Missouri), Kelsey Care (Texas) and Geisinger Gold (Pennsylvania and New Jersey).

Plans having many enrollees are sometimes the best because if it's popular in your area, it suggests others are happy with its coverage. 

But there are more objective ways of distinguishing the fair or the good from the very best.

Medicare star ratings are a more objective measure of quality and suitability

Medicare Advantage plans are given a yearly star rating by the Medicare program. The best plans are given five (out of five) stars.  

Ratings are based on things like member satisfaction, quality of care, customer service, complaints and more. 

These ratings are important to insurance companies  because the money Medicare gives them is based in part on the number of stars they earn. Plans with the highest ratings are given extra money.

Every plan must publish its star rating and give people more details if they ask. If you are considering a Medicare Advantage plan, you should understand its star rating and how it compares to other plans in your area. 

Most insurance companies have several Medicare contracts, each with its own star rating. This means a company like Aetna could have a five star plan in one part of the country and a two star plan in another.

Most plans earn four stars; that's a good rating. 

Very low and very high ratings are both uncommon. In 2021, only five percent of all contracts earned five stars, the highest number possible.

Only four contracts earned 2.5 stars, the lowest score given by Medicare this year. Companies having fewer than three stars are at risk of losing their Medicare contract.

Are the most expensive plans the best?

While the majority of Medicare Advantage plans have a $0 monthly premium, the benefits, networks and out of pocket costs will vary. Some people look to that information as a way of finding their own "best" plan.

Use caution when using monthly premiums as a measure of quality because the way our government funds these plans is complicated.

Sometimes a plan costs a lot of money because it's full of generous benefits or has a giant doctor network. You'll pay extra for that kind of coverage.

In other cases, it's expensive for reasons having nothing to do with generosity and might even indicate future problems. Maybe the company just isn't good at negotiating prices or managing the care of their enrollees.

Be sure you understand these things before you make a coverage decision. Never enroll in a plan you do not understand.