The [Affordable Care Act's] largest impact on labor markets will probably occur after 2016, once its major provisions have taken full effect and overall economic output nears its maximum sustainable level. CBO estimates that the ACA will reduce the total number of hours worked, on net, by about 1.5 percent to 2.0 percent during the period from 2017 to 2024, almost entirely because workers will choose to supply less labor—given the new taxes and other incentives they will face and the financial benefits some will receive. Because the largest declines in labor supply will probably occur among lower-wage workers, the reduction in aggregate compensation (wages, salaries, and fringe benefits) and the impact on the overall economy will be proportionally smaller than the reduction in hours worked. . . .

CBO's estimate that the ACA will reduce employment reflects some of the inherent trade-offs involved in designing such legislation. Subsidies that help lower-income people purchase an expensive product like health insurance must be relatively large to encourage a significant proportion of eligible people to enroll. If those subsidies are phased out with rising income in order to limit their total costs, the phaseout effectively raises people's marginal tax rates (the tax rates applying to their last dollar of income), thus discouraging work. In addition, if the subsidies are financed at least in part by higher taxes, those taxes will further discourage work or create other economic distortions, depending on how the taxes are designed. Alternatively, if subsidies are not phased out or eliminated with rising income, then the increase in taxes required to finance the subsidies would be much larger."