A Medicare Advantage plan works differently than a Medicare Supplement plan. With a Medicare Advantage plan, a private company serves as the administrator – or, payor – for your Medicare coverage. This simply means that while you still have Medicare, Medicare is no longer responsible for your bills; the Medicare Advantage plan is. Medicare Advantage plans follow the same type of model as many group plans such as a Health Maintenance Organization, or HMO, or Preferred Provider Organization, or PPO. In some states, there are also private-fee-for-service plans. With a Medicare Advantage plan, it is important to remember several things. First, most Medicare Advantage plans have a network of doctors from which to choose. So, you want to make sure your doctor, hospital, and auxiliary care are within the network. While a PPO plan will allow you to visit providers outside of the plan’s network, you may experience higher costs, and in some cases, you may be responsible for 100% of care outside the network (if the provider does not accept the Medicare Advantage plan). Medicare Advantage plans that use the HMO model require its members to use only the doctors in the network, the only exception being in the event of an emergency. In addition, it is important to remember that Medicare Advantage plans have co-pays and other out-of-pocket expenses that are associated with the plan.