What is a key difference between group health insurance and individual health insurance?

GROUP vs INDIVIDUAL HEALTH INSURANCE: GROUP INSURANCE: Covers members of a GROUP (typically employees of an employer, or members of an association) under one MASTER POLICY held by the employer/group; ADVANTAGES: often LOWER per-person cost (risk spread over the group, employer often pays part of the premium); SIMPLIFIED or NO individual underwriting (guaranteed coverage for eligible members — the group is underwritten, not each person); a certificate of coverage is issued to members; INDIVIDUAL INSURANCE: Purchased by a person DIRECTLY (e.g., via the ACA marketplace or directly from an insurer); historically individually underwritten/rated (though ACA limits health-based rating for major medical); the individual owns the policy (portable — not tied to a job); EMPLOYER GROUP plans: a major source of coverage in the US; ACA: Changed individual market underwriting (guaranteed issue, no health rating); the group vs individual distinction (group = master policy, lower cost, simplified underwriting, employer-based; individual = directly purchased, portable) is fundamental health insurance exam content.