There is no precise headcount of how many people have gained coverage because of the Affordable Care Act. And it is downright impossible to reliably estimate the number of people who might lose coverage if Congress repeals and replaces it. The “20 million” figure appears to have originated in a March 2016 report by the U.S. Department of Health and Human Services. That report declared that “the provisions of the ACA have resulted in gains in health insurance coverage for 20.0 million adults through early 2016.”
Estimates by the Heritage Foundation find that 14 million people (including children) gained public or private coverage in 2014 and 2015. Unlike government surveys, Heritage examined data from insurance company regulatory filings and from the government’s own headcount of Medicaid enrollment.
They found that 84% of the newly insured gained coverage through Medicaid and a related government program for low-income children.
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