The architects of the Affordable Care Act thought they had a blunt instrument to force people—even young and healthy ones—to buy insurance through the law’s online marketplaces: a tax penalty for those who remain uninsured. The full weight of the penalty will not be felt until April, when those who have avoided buying insurance will face penalties of around $700 a person or more. But for the young and healthy who are badly needed to make the exchanges work, it is sometimes cheaper to pay the Internal Revenue Service than an insurance company charging large premiums, with huge deductibles. The IRS says that 8.1 million returns included penalty payments for people who went without insurance in 2014, the first year in which most people were required to have coverage.

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