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State Estimates of Access to Care: National Health Interview Survey

By: The Office of Planning, Budget, and Legislation at the National Center for Health Statistics (NCHS)

Last month the National Health Interview Survey (NHIS) published 2015 estimates of health insurance coverage for all 50 states and the District of Columbia in its report, Health Insurance Coverage: Early Release of Estimates From the National Health Interview Survey, 2015. This report was important for two reasons. First, the percentage of uninsured persons reached a historic low of 10.5% for persons under 65 years in 2015. Second, this is the last report in the foreseeable future that provides estimates for all 50 states and the District of Columbia.

Increased investment in NHIS has allowed the survey to document historical changes related to health care since the passing of the Affordable Care Act (ACA). The ACA established the Prevention and Public Health Fund to provide expanded investments in prevention and public health. With these funds as well as further investment from the Centers for Disease Control and Prevention (CDC), the NHIS survey expanded to include more state estimates beginning in 2011. The sample grew steadily each year from its baseline of about 35,000 households in 2010 to almost 45,000 households in 2014. This increase in sample size allowed NCHS to document changes in the number and percentage of uninsured not only nationally, but for 50 states and the District of Columbia as well.

NCHS takes pride in its ability to remain neutral on policy to protect the integrity of its analysis and provide valuable data for policymakers, researchers, and the public. There was a huge interest in NHIS throughout the early years of ACA implementation. Each quarterly release of estimates was met with anticipation for documentation of changes in the health care system, as the NHIS was the only national health survey able to produce statistically reliable health insurance coverage estimates in all 50 states and the District of Columbia. State estimates grew more important to researchers and policymakers as a number of states chose not to expand Medicaid—an important component of the ACA.

The NCHS report released last month reported that from 1997 through 2010, the percentage of adults aged 18–64 who were uninsured at the time of interview generally increased, but more recently, the percentage of uninsured decreased from 22.3 percent in 2010 to 12.8 percent in 2015. During this 5-year period, corresponding increases were seen in both public and private coverage among adults 18-64. The percentage of children who were uninsured decreased from 13.9 percent in 1997 to 4.5 percent in 2015. From 1997 through 2010, the percentage of children with private coverage generally decreased and the percentage of children with public coverage generally increased. However, more recently, the percentage of children with public or private coverage has leveled off.

The sample expansion of NHIS allowed for other detailed analysis of state comparisons. For example, in May of 2016 NCHS also released, State Variation in Health Care Service Utilization: United States, 2014which found that the percentage of adults without a usual place of medical care ranged from 2.8 percent in Vermont to 26.7 percent in Nevada.


While the sample expansion has allowed for state estimates for all states and the District of Columbia for the 2014 and 2015 NHIS, the 2016 NHIS will reduce the sample by several states due to lack of funds. The 2017 NHIS will return to the survey’s baseline and will be nationally representative, but the ability to produce state estimates will be limited to approximately 20 states, ending an important era in the survey’s almost 60-year history.

This blog post is sponsored by the Friends of NCHS; it originally appeared on the AcademyHealth blog.