How American healthcare is actually structured

Interviewers rarely ask you to describe the system. They ask something that only makes sense if you already can: why a patient skipped a prescription, why a hospital closed, why an insurer denied a claim, why two people with the same diagnosis got different care. Applicants who have never mapped the system answer those from instinct, and instinct produces confident nonsense.

What follows is the minimum structure to hold. It is dull to learn and it quietly powers everything else — the drug-pricing story, the physician shortage, every ethics scenario involving cost.

Roughly half of Americans get coverage through an employer, a legacy of wage controls in the 1940s that made health benefits a way to compete for workers, later locked in by a tax exemption. About one in five are on Medicare, one in five on Medicaid or the children’s program CHIP, a smaller share buy on the ACA marketplaces, and around one in twelve have nothing. The categories overlap — some people are dually enrolled in Medicare and Medicaid — and people move between them with jobs, ages and incomes.

Medicare has parts: A for hospital care, B for outpatient and physician services, D for prescription drugs, and C, Medicare Advantage, in which private plans deliver the whole package under contract and now cover more than half of enrollees. Medicaid is run by each state within federal rules and funded jointly; the ACA offered states money to expand it to all low-income adults, and as of the mid-2020s about forty states had, leaving a coverage gap in the rest. The marketplaces sell regulated private plans with income-based subsidies. The uninsured pay list prices, which are the highest prices in the system.

The system was not designed; it accreted. Four moments explain most of its shape.

Then the bodies applicants habitually mix up. The Centers for Medicare & Medicaid Services runs the two big public programs and, through them, sets payment rates that private insurers benchmark against. The Food and Drug Administration decides whether a drug or device is safe and effective enough to be sold — a different question, asked first, from whether anyone will pay for it. State insurance commissioners regulate private plans sold in their state, and state medical boards license physicians, which is why scope-of-practice fights happen in fifty legislatures rather than one. The Department of Health and Human Services sits over the federal pieces.

Providers are paid mostly per service, which rewards volume, with a growing share under arrangements that pay for outcomes or bundles. Hospitals negotiate different prices with every insurer and post list prices few people pay in full. The result is the feature every visitor finds strangest: the same procedure in the same building can carry a dozen prices depending on who is paying.

Structure questions arrive in three shapes. The direct one: "What is the difference between Medicare and Medicaid?" The applied one: "A patient can’t afford their medication. What do you do?" And the disguised one, where the system is never mentioned but every good answer needs it — "What is the biggest problem in American healthcare?"

For the direct question, define, date and add the why. For the applied question, walk the patient’s coverage route out loud. For the disguised question, pick one problem and trace it through the system rather than listing five.

The best single primer is the KFF explainer series on how coverage works, which is short, current and free of jargon. Then read the CMS pages on Medicare’s parts and the Medicaid expansion map, because the state-by-state detail is where interview follow-ups go.

Two pieces here trace one thread each through the structure. Drug prices and the negotiation era follows the money from list price to patient, and the scope-of-practice fight shows why state boards matter more than federal ones. For the application itself, start with our guide to getting into medical school in the US.