The Affordable Care Act (ACA) includes a provision, generally called the individual mandate, that requires most U.S. citizens and noncitizens who lawfully reside in the country to have health insurance meeting specified standards and that imposes penalties on those without an exemption who do not comply. In response to interest from Members of Congress, CBO and the staff of the Joint Committee on Taxation (JCT) have updated their estimate of the effects of repealing that mandate. As part of repealing the mandate, the policy analyzed would eliminate the penalty that people who have no health insurance and who are not exempt from the mandate must pay under current law.

The analysis underlying this estimate incorporates revised projections—of enrollment in health insurance, premiums, and other factors—made as part of the usual process CBO follows to update its baseline projections. This report updates a budget option published in December 2016 and is not based on specific legislative language.

The Results of CBO and JCT’s Analysis

CBO and JCT estimate that repealing that mandate starting in 2019—and making no other changes to current law—would have the following effects:

Federal budget deficits would be reduced by about $338 billion between 2018 and 2027.

The number of people with health insurance would decrease by 4 million in 2019 and 13 million in 2027.

Nongroup insurance markets would continue to be stable in almost all areas of the country throughout the coming decade.

Average premiums in the nongroup market would increase by about 10 percent in most years of the decade (with no changes in the ages of people purchasing insurance accounted for) relative to CBO’s baseline projections.

Those effects would occur mainly because healthier people would be less likely to obtain insurance and because, especially in the nongroup market, the resulting increases in premiums would cause more people to not purchase insurance.

If the individual mandate penalty was eliminated but the mandate itself was not repealed, the results would be very similar to those presented in this report. In CBO and JCT’s estimation, with no penalty at all, only a small number of people who enroll in insurance because of the mandate under current law would continue to do so solely because of a willingness to comply with the law. If eliminating the mandate was accompanied by changes to tax rates or premium tax credits or by other significant changes, then the policy analyzed here would interact with those changes and have different effects.

For this analysis, CBO and JCT have measured the budgetary effects relative to CBO’s summer 2017 baseline, which underlies the Concurrent Resolution on the Budget for Fiscal Year 2018. In that baseline, the ACA’s other provisions, including premium tax credits and cost-sharing reduction (CSR) subsidies in the marketplaces that the legislation established, are assumed to remain in place.

In the budget option presented last year, CBO and JCT examined the same policy starting a year earlier and relative to CBO’s March 2016 baseline: They estimated that the policy would reduce federal budget deficits by $416 billion between 2018 and 2026 and increase the number of uninsured people by 16 million in 2026.

The differences between the budgetary effects shown here and those estimated in December 2016 stem from several sources. The current estimate relies on updated baseline projections related to the federal costs of subsidizing health insurance. This estimate also incorporates CBO and JCT’s expectation that individuals’ and employers’ full reaction to the elimination of the individual mandate would phase in more slowly than the agencies previously projected. (The agencies have incorporated that expectation in all estimates for legislative proposals related to the mandate that they have prepared after the 2017 budget reconciliation process ended in September.) And this estimate includes an interaction with Medicare, whose “disproportionate share hospital” payments to facilities that serve a higher percentage of uninsured patients would be affected.

In addition to updates to the baseline, which occur on a regular cycle, CBO and JCT sometimes make major methodological changes to improve their estimates. Accordingly, the agencies have undertaken considerable work to revise their methods to estimate the effects of repealing the individual mandate. CBO’s Panel of Health Advisers and experts at the American Enterprise Institute, the Office of the Actuary in the Centers for Medicare & Medicaid Services, the RAND Corporation, and the Urban Institute, along with other sources, have provided valuable information during that process. However, the evidence available to inform CBO and JCT’s work on that issue is limited. Because that work is not complete and significant changes to the individual mandate are being considered as part of the budget reconciliation process, the agencies are publishing this update now without incorporating major changes to their analytical methods.

However, the preliminary results of analysis using revised methods indicates that the estimated effects on the budget and health insurance coverage would probably be smaller than the numbers reported in this document. The agencies are continuing to work on those methods, and they expect to complete and publish an estimate including and explaining the revisions at some point after the current budget reconciliation process is complete or along with a future update to the baseline.

Uncertainty Surrounding the Estimates

CBO and JCT’s estimates of this policy are inherently imprecise because the ways in which federal agencies, states, insurers, employers, individuals, doctors, hospitals, and other affected parties would respond to it are all difficult to predict. The responses by individuals in the short term to a policy that would repeal the mandate are uncertain, for example.

The policy’s nonfinancial effects—changes in people’s tendency to comply with laws and attitudes about health insurance and their greater responsiveness to penalties than to subsidies—amplify its financial effects in CBO and JCT’s analysis. The amplification from those nonfinancial effects is harder to project. In large part because of the difficulty in projecting that amplification, different organizations’ estimates of the effects of repealing the mandate have varied. The effects could be smaller than those presented here: Some organizations have recently published such smaller estimates that appear to ascribe lesser effects to nonfinancial factors. Alternatively, the nonfinancial effects of the mandate might grow over time—as the effects of many provisions of the tax code appear to have done after their implementation and as could occur if awareness and enforcement of the mandate changed. Under that circumstance, the effects of repealing the mandate could be larger over time.

CBO and JCT’s baseline projections are also uncertain, and revisions to them would alter interactions and change the estimates of the effects of eliminating the mandate. For example, if there are no payments for CSRs, premiums in the marketplaces would probably be higher than projected in the baseline. (The Administration has halted those payments, but the baseline projections used in this estimate incorporated the assumption that they would continue.) Premiums that are higher than those in the baseline projections would tend to boost the budgetary savings under this policy by increasing the estimated per-person savings from people no longer enrolling in nongroup coverage. As another example, subsidized enrollment in the marketplaces might be lower than projected in the baseline, which would tend to decrease the budgetary savings under this policy.

Despite the uncertainty, some effects of this policy are clear: For instance, the federal deficit would be many billions of dollars lower than under current law, and the number of uninsured people would be millions higher.