The ACA's dependent coverage mandate increased the percentage of 19-25 year olds with health insurance from 66 to 70 percent, an increase of about 938,000 individuals.
The Affordable Care Act (ACA) required that health insurers extend dependent coverage to the children of their insured by September 22, 2010, as long as those children were under age 26, and regardless of whether they were married, dependent on their parents, or occupying a different residence. There were an estimated 29.5 million adults in the age category affected by the dependent coverage mandate, and insurers were not allowed to charge any more for this type of coverage than they did for coverage of younger children.
In Effects of Federal Policy to Insure Young Adults: Evidence From the 2010 Affordable Care Act Dependent Coverage Mandate (NBER Working Paper No. 18200), Yaa Akosa Antwi, Asako Moriya, and Kosali Simon estimate that the ACA's dependent coverage mandate increased the percentage of 19-25 year olds with health insurance from 66 to 70 percent, an increase of about 938,000 individuals. Prior to the law's implementation, the federal government had estimated that dependent coverage would produce overall gains in health insurance somewhere in the range of 190,000 to1.64 million individuals.
The authors conclude that the ACA "erased about one-third of the uninsurance among targeted individuals" with parental, employer supplied insurance. The increase in dependent coverage came both from those who were otherwise uninsured and from those who were either insured by their own employer or had individually purchased policies. Even though there was greater take-up of coverage when the marginal cost of adding an individual was low, around 13 percent of eligible dependents remained uninsured despite the fact that their parents had employer supplied policies. There was no evidence that the dependent coverage mandate affected the probability of employment, but the authors did find that the law was associated with a reduced prevalence of full-time work and a statistically significant reduction in hours of work.