Signs Point to Affordable Care Act's Impact on Increasing Health Insurance Coverage

Two sources of contemporaneous data available from reputable national research institutions provide evidence that the Affordable Care Act has realized its principal goal of increasing the rate of health insurance coverage in the United States. The rates of uninsured Americans between late 2013 and early 2015 have dropped from 18 percent to 11.9 percent, according to Gallup, and from 17.4 to 10.1 percent, according to the Urban Institute. Further, the Gallup data which also provide state-by-state statistics show that the states with the greatest uptake in health insurance were more likely to have increased Medicaid eligibility and to operate state-based health insurance exchanges

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About the Author

Debra Miller is director of health policy in The Council of State Governments’ national headquarters office in Lexington, Ky. She has over thirty years of experience analyzing states’ health programs for low- and middle-income children and adults. Her work has appeared in the 2010, 2012 and 2014 volumes of The Book of the States.

Large on-going survey efforts by both Gallup and the Urban Institute conclude that significantly fewer American adults remain without health insurance since the implementation of two key components of the Affordable Care Act in 2014: health insurance exchanges—and the availability of tax subsidies to offset premium costs—and Medicaid expansion.

Uninsured Rate Falls Nationally

The Gallup-Healthways Well-Being Index has tracked the percentage of Americans, ages 18 to 65, without health insurance since early 2008. According to Gallup’s latest data for the first quarter of 2015, the rate of uninsured people has dropped to 11.9 percent from 18 percent in the last quarter of 2013, before the implementation of the ACA’s major insurance coverage provisions.1 (See Figure A.)

The Urban Institute’s Health Reform Monitoring Survey data, in a national sample, indicate that 10.1 percent of adults remained uninsured in the first quarter of 2015, down from 17.4 percent in the last quarter of 2013.2 (See Figure A.)

The end of the first quarter of 2015 coincided with the close of the 2014–15 open enrollment period for purchasing insurance and qualifying for tax subsidies through the ACA health exchanges, as well as the imposition of tax penalties for those who do not have health insurance. The 2014–15 open enrollment period was the second under the ACA.

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Uninsured Rate Falls in 2014 for all States Except Kansas

Between 2013 and 2014, according to the Gallup-Healthways data, uninsured rates fell in all states except Kansas.3 (See Table A.)

The states with the 10 biggest drops in rates of the uninsured, with exception of Montana, made the state decision to expand Medicaid. These states range from Arkansas—with an 11.1 percentage point drop—to Montana and New Mexico, tied with 4.9 percentage point decreases. And all states, except Kansas, had some drop in their rate of uninsured residents.

In its methodology notes, Gallup reported the sampling error—the survey was conducted by landline and cellular telephone—is plus or minus one to two percentage points except for the states with the smallest populations, such as Alaska, North Dakota, Vermont and Wyoming, where the sampling error is close to plus or minus 4 percentage points. The vast majority of states’ change in insurance coverage did not fall within the sampling error.4

Did the Affordable Care Act Make a Difference?

Of the states with the biggest drop in rates of the uninsured between 2013 and 2014 (see Figure B), only Montana did not chose to expand Medicaid eligibility. The June 2010 decision of the U.S. Supreme Court made Medicaid expansion a state option, not a state mandate.

During 2014, 25 states and the District of Columbia expanded income eligibility for Medicaid under the Affordable Care Act option. Wisconsin already had in place eligibility to the federal poverty level under a previously approved waiver. Pennsylvania’s Medicaid expansion began on Jan. 1, 2015, and Indiana’s expansion began on Feb. 1, 2015.

In the remaining 22 states, some low-income adults without children remain in the coverage gap between Medicaid and eligibility for tax subsidies to offset the premium prices of policies purchased through the health exchanges. This coverage gap in the states that have so far decided against expanding Medicaid eligibility has been estimated by the Kaiser family Foundation to impact about 4 million Americans.5 Kaiser determined 43 percent of adults in the coverage gap are full-time workers, 36 percent are between 35 and 54 years old, 82 percent are in excellent, very good or good health; and 43 percent are white.6

Only three of the states with the top performance in terms of increasing health insurance coverage did not create state-based health exchanges. While the performance of the state-based exchanges and the federal exchange differed, all individuals who purchased insurance through the exchanges were assessed for eligibility for tax subsidies to increase the affordability of premiums. CSG estimated, based on U.S. Department of Health and Human Services data, that the total annual value of tax subsidies in 2015 will be approximately $34 billion.7

The decision of states to create their own state-based exchanges, or by default to depend upon the federally operated exchange,, may have repercussions on health insurance coverage rates if the Supreme Court finds in favor of the plaintiffs in the King v. Burwell case. A decision is expected by the end of June 2015. CSG calculated the annual value of the subsidies at risk tops $24 billion and benefits 7.7 million individuals in the 34 states where the Supreme Court could declare subsidies unlawful.8


1 Jenna Levy, “In U.S., Uninsured Rate Dips to 11.9% in First Quarter,”, April 13, 2015,
2 Sharon Long, et al., “Taking Stock: Gains in Health Insurance Coverage under the ACA as of March 2015,” Urban Institute Health Policy Center, April 16, 2015,
3 Dan Witters. “Arkansas, Kentucky See Most Improvement in Uninsured Rates,”, Feb. 24, 2015,
4 Ibid.
5 Rachael Garfield, et al., “The Coverage Gap: Uninsured Poor Adults in States that Do Not Expand Medicaid—An Update,” Kaiser Family Foundation, April 17, 2015,
6 Ibid.
7 Debra Miller, “Insurance Subsidies at Risk in Supreme Court’s King v. Burwell Case,” The Council of State Governments, March 30, 2015,