Which of the following plans generally requires referrals to see specialists?

Health Maintenance Organizations (HMOs) are designed to manage patient care through a structured network of providers and facilities. One of the key features of HMOs is that they typically require members to select a primary care physician (PCP). This PCP serves as a gatekeeper for the patient's healthcare needs and is responsible for coordinating care.

When a patient needs to see a specialist, they usually must first obtain a referral from their primary care physician. This process ensures that patients receive appropriate and necessary care while also helping the HMO control costs by directing patients within its network of providers. The referral requirement is a critical aspect of the HMO model, emphasizing a more managed approach to healthcare.

In contrast, other plans such as Preferred Provider Organizations (PPOs) allow members greater flexibility to see specialists without needing a referral, while catastrophic and short-term health plans have varying structures that do not typically implement the same referral requirements as HMOs.