What is the difference between an HMO and a PPO?

HMO (Health Maintenance Organization): requires insured to choose a PCP; must get referrals from PCP to see specialists; only in-network providers covered except emergencies; lower premiums; less flexibility. PPO (Preferred Provider Organization): no PCP requirement; no referrals needed; can see any provider in or out of network; in-network costs less; more flexibility; higher premiums. EPO (Exclusive Provider Organization): like PPO (no referrals) but no out-of-network coverage (like HMO). Point of Service (POS): hybrid — has a PCP but allows out-of-network at higher cost.