In a PPO and Open Access HMO, doctors agree to provide their services to the plan's members at a lower price in exchange for that health plan encouraging it's members to use those doctors. The doctors like it because they get more patients, and the health plan likes it because it save money. Consumers like it because it costs less and the benefits are richer. Members still receive full benefits within the HMO network. A relatively new kind of coverage usually only available with group plans.
Members can even go directly to specialists without a referral.
PPO's offer cost-sharing incentives to encourage members to use a network of participating providers with whom the plan negotiates discounted rates. The networks are usually very large, and the members are free to seek care from any physician or provider within the network or outside the network. Obviously, the member gets better coverage if he or she uses physicians and hospitals within the network. These benefits come in the form of front-end copayments and lower coinsurance.