WASHINGTON, D.C. -- The uninsured rate among adults aged 18 and older in the states that have chosen to expand Medicaid and set up their own exchanges in the health insurance marketplace has declined significantly more this year than in the remaining states that have not done so. The uninsured rate, on average, declined 2.5 percentage points in the 21 states (plus the District of Columbia) that have implemented both of these measures, compared with a 0.8-point drop across the 29 states that have taken only one or neither of these actions.

As Gallup previously reported, the states that have chosen to expand Medicaid and set up their own healthcare exchanges had a lower average uninsured rate to begin with: 16.1% compared with 18.7% for the remaining states -- a difference of 2.6 points. The already notable gap between the two groups of states widened in the first quarter to 4.3 points.

Nationally, 17.3% of U.S. adults reported being without health insurance in 2013, a rate that had slowly increased from 14.8% in 2008. The uninsured rate peaked at 18.0% in the third quarter of 2013 -- the three months immediately preceding the opening of the healthcare exchanges -- and has since declined to 15.6%.

These data, collected as part of the Gallup-Healthways Well-Being Index, are based on Americans' self-reported insurance status in response to the question, "Do you have health insurance coverage?"

Some states have chosen to implement state-federal "partnership" exchanges, for which states run certain functions and make key decisions based on local market and demographic conditions. For the purposes of this analysis, these partnerships are included with the state exchanges. Only four states -- North Dakota, New Jersey, Ohio, and Arizona -- have decided to expand Medicaid without also administering a state-based exchange, while several others continue to debate expanding eligibility.

See page 2 for a full list of the status of Medicaid expansion and healthcare exchanges for all states, as well as the 2013 uninsured rates for each.

Implications

While a majority of Americans continue to disapprove of the Affordable Care Act, also known as "Obamacare," the uninsured rate appears to be declining, as the law intended. In turn, the states (including the District of Columbia) that have implemented two of the law's core mechanisms -- Medicaid expansion and state health insurance exchanges -- are realizing a rate of decline that is substantively greater than what is found among the remaining states that have not done so. Consequently, the gap that previously existed between the two groups has now expanded.

Many states continue to debate implementing these measures. Nebraska's state government recently voted down Medicaid expansion, while New Hampshire voted to expand, effective July 1. Perhaps no state is being watched more closely than Utah, a conservative state with a Republican governor, Gary Herbert, that is considering Medicaid expansion but under revised, more flexible terms than what the Affordable Care Act provides. These plans, which include a three-year block grant to cover about 110,000 low-income residents with private insurance, plus cost sharing and work requirements, have fueled ongoing conversations with federal officials at the Centers for Medicare & Medicaid Services. The resolution of these negotiations and Utah's final decision may ultimately pave the way for more conservative-leaning states to follow, which could prove to be the best source of continued decline in the national uninsured rate in the months ahead.