HMO – Health Maintenance Organization
An HMO requires you to designate a primary care provider (PCP), who serves as a “gatekeeper,” providing general health care and referrals to in-network providers as needed. It is more restrictive than a PPO in that if you go to a doctor who is not in the network or even see an in-network specialist without a referral, your expenses will not be covered.

PPO (Preferred Provider Organization)/POS (Point of Service)
A PPO or POS plan means you can decide at the point of service–that is, when you need health care–whether to see an in-network provider and receive a higher level of benefits or an out-of-network provider and receive a lower level of benefits. You may see specialists without a referral, and switch between in-network and out-of-network providers. You do not need to designate a PCP.

HDHP (High Deductible Health Plan)
An HDHP is a fast growing option – because it is typically much cheaper than the other health plans.  Just like its name suggests, an HDHP has a much higher deductible (between $1,500 and $5,000).  While this may seem like a lot, it should be noted that often, there is no coninsurance, meaning that once your deductible is paid, your remaining expenses are covered 100%.  In fact, this is a requirement for an HDHP to qualify for an HSA.