Researchers Find ‘Woodwork Effect’ With Medicaid Enrollment

New research shows that when adults enroll in Medicaid they are also likely to enroll their eligible children. The additional enrollment, known as the “woodwork effect,” was shown in a paper published Aug. 9 in the American Economic Journal: Economic Policy.
The study used data from the Oregon Health Insurance Experiment of 2008, which ran a lottery for new Medicaid entry.
Researchers found that for every nine adults enrolled in the Medicaid program in Oregon due to the special lottery, one child was added to the Medicaid roll.
Under the Affordable Care Act some states expanded their Medicaid program to additional low-income adults, while other states did not.
The study also finds that while the woodwork effect might increase children’s enrollment into Medicaid, it would not necessarily increase the cost for taxpayers, as the cost of covering children through Medicaid is about four times less than adults.
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