When the Balanced Budget Act of 1997 became law, Medicare beneficiaries were given the option to receive benefits through private health insurance plans, instead of through the traditional Medicare program.
The private-company options were known as Medicare+Choice or Part C plans.
Those options were made more attractive with passage of the Medicare Prescription Drug, Improvement and Modernization Act of 2003, which added prescription drug coverage to the private plan options, which then became known as Medicare Advantage plans.
Traditional Medicare has a standard benefit package with services available from almost any hospital or doctor in the nation.
For those in a Medicare Advantage plan, the government pays the private health plan operator a set amount each month per member. Members typically receive benefits not covered by traditional Medicare, such as dental care or health club membership.
In exchange for the extra benefits, enrollees may be limited in the providers they can see. Medicare Advantage plans typically have a provider network. Plan members who go outside the network may incur extra fees.
Nationally, enrollment in Medicare Advantage plans has grown steadily the past few years.
Critics of Medicare Advantage say the plans cost taxpayers at least 12 percent more than traditional Medicare but benefit the insurance companies more than plan members.
Supporters of Medicare Advantage say enrollees on average spend fewer days in the hospital than traditional Medicare beneficiaries and fewer are re-admitted to the hospital.
Some studies show that those who are older, sicker or poorer are less satisfied with Medicare Advantage.