Defensive Medicine and the Economics of Malpractice

A doctor examines a patient with a minor head bump after a low-speed fall, sees nothing concerning, and would ordinarily send the patient home with instructions to watch for symptoms. Instead, the doctor orders a CT scan - not because it’s medically necessary, but because if something rare and serious turns out to be wrong later, having ordered the scan protects the doctor from a lawsuit claiming it should have been caught. This pattern has a name: defensive medicine, the practice of ordering tests, procedures, or referrals primarily to reduce legal risk rather than because they’re expected to meaningfully help the patient.

Where the incentive comes from

Doctors in most countries, and especially in the United States, can be sued for malpractice liability - legal responsibility for harm caused by care that fell below the accepted standard of care, the level of skill and caution a reasonably competent provider in the same situation would have exercised. This liability exists for a genuinely good reason: it gives providers a real incentive to practice carefully and gives patients some recourse when they’re harmed by actual negligence. The trouble is what happens once providers start optimizing not just for good outcomes, but for a defensible paper trail in case something goes wrong regardless of whether anyone was actually negligent.

Because a lawsuit can be filed even when a doctor’s judgment was reasonable, and because juries don’t always share a physician’s clinical judgment about what precaution was actually necessary, providers face pressure to over-order tests and treatments as a form of insurance against being second-guessed later - not against being wrong, but against being blamed.

The bill for playing it safe

Estimates of defensive medicine’s total cost vary widely depending on how it’s measured, but most economic studies place it in the tens of billions of dollars annually in the United States alone, once unnecessary imaging, lab tests, specialist referrals, and hospital admissions are all added up. That’s a real cost borne broadly by insurers, taxpayers funding public programs, and ultimately patients through higher premiums, even though no individual patient asked for the extra caution and most never learn it happened.

Defensive medicine also interacts with medical liability insurance, the coverage most providers carry specifically to pay for legal defense costs and any judgments against them. In regions or specialties where lawsuits and payouts are more common - obstetrics is a frequently cited example - liability insurance premiums for providers rise sharply, which can push some providers to stop offering higher-risk services altogether, or relocate to a state with different liability rules, an effect on physician supply that’s distinct from, but layered on top of, the defensive-medicine testing pattern itself.

Attempts to fix the incentive

Some states have experimented with capping the dollar amount a patient can recover for non-economic damages like “pain and suffering” in a malpractice case, aiming to reduce unpredictable, extremely large jury awards and, in theory, ease the pressure toward defensive ordering. Evidence on whether these caps actually reduce defensive medicine in practice is mixed - they may lower liability insurance costs for providers without meaningfully changing how many extra tests get ordered, since the instinct to avoid being second-guessed doesn’t disappear just because a potential payout shrank.