Insurance coverage

Columbia University Mailman School of Public Health – InsuranceNewsNet

August 19, 2022 (NewsRx) — By a News Reporter – Staff News Editor, Education Daily Report — Expanding Medicaid coverage for adults also helps cover children, says new study by researchers at Columbia University Mailman School of Public Healththe University of Chicagoand MIT. The study looked at Oregon’s 2008 Medicaid lottery and found that for every nine adults who got medical coverage, one additional child also signed up. The research describes the impact of expanding adult Medicaid eligibility on enrollment of already eligible children.

The findings of the article, “Out of the Woodwork: Enrollment Spillovers in the Oregon Health Insurance Experiment,” are published in the August 2022 problem of American Economic Review: Economic policy.

In the lottery, some low-income uninsured adult enrollees were randomly selected to be eligible to apply for Medicaid. Winning or losing the lottery did not change if their children were eligible for coverage. The researchers asked whether expanding eligibility for one group, adults, helped cover another group, their children. Previous studies have referred to this phenomenon as the “carpentry effect” or the “welcome mat effect”.

“Our study shows that expanding Medicaid eligibility can improve insurance coverage rates for people who weren’t even the target of the expansion,” said Adam SacarnyPhD, first author of the study and assistant professor of health policy and management at Public Health of Colombia. “In this case, when the adults signed up for Medicaid, their children were also covered.”

Medicaid provides health insurance coverage to 81 million people in the WE, including 34 million children. About 7% of Medicaid-eligible children have not purchased coverage and remain uninsured. The paper adds to the existing literature on barriers to enrollment in health insurance and other social programs. It also sheds new light on the policies of the Affordable Care Act of 2010, which included an expansion of Medicaid to cover low-income people. Researchers studied an earlier randomized adult Medicaid expansion that took place in 2008 in Oregon.

“This research highlights the value of conducting further secondary studies of randomized trials,” Sacarny said. “When you combine trials with additional administrative data, you can use them to investigate additional questions that are potentially very important for economic and social policy.”

The study also provides new perspective on the broader impacts of Medicaid coverage extensions. “We found evidence for these carpentry effects,” the co-author said. Amy FinkelsteinPhD, professor at MIT Department of Economics. “We reject the hypothesis that these types of fallout do not occur. On the other hand, compared to claims in the media and in some previous work of potentially large carpentry effects greater than half the direct effect, our effects are quantitatively much smaller than had been conjectured.

Although the researchers found significant effects on carpentry, they also found that the effects were short-lived. They showed that children of lottery winners saw an immediate increase in coverage when their parents signed up, but children of lottery losers also got coverage. “Therefore, our results suggest that the effects of carpentry primarily encourage earlier enrollment of children who otherwise would have obtained coverage later,” Sacarny observed.

The results point to two reasons why coverage is incomplete among those eligible for Medicaid, according to Sacarny. First, Medicaid eligibility rules can be complicated and some families may not be familiar with them. In this experience, when adults “earned” the opportunity to enroll in Medicaid, they may have learned of their children’s eligibility. Second, applying for Medicaid can be cumbersome: in the days when Oregon, the application package was 46 pages long with up to 19 pages of prompts to fill out. However, since the application was for an entire household, an adult signing up could easily include their children.

“Incomplete enrollment in social insurance programs is pervasive, including the Medicaid program,” Saccarny said. “This study demonstrates the many ways that randomized trials, like the one in Oregon, can be used to generate other outcomes. Given a valid experience, researchers can think creatively about how to identify its effects and continue to build on that experience to produce rigorous results.

Catherine Baickerprofessor and dean at the University of Chicago Harris School of Public Policyis co-author.

The study was supported by the National Institute of Aging.

Columbia University Mailman School of Public Health

Founded in 1922, the Columbia University Mailman School of Public Health pursues an agenda of research, education and service to address critical and complex public health issues affecting New Yorkers, the nation and the world. The Columbia Mailman School is the fourth largest beneficiary of NIH grants between schools of public health. Its nearly 300 multidisciplinary faculty work in more than 100 countries around the world, addressing issues such as infectious and chronic disease prevention, environmental health, maternal and child health, health policy, climate change and health, and public health preparedness. It is a leader in public health education with more than 1,300 graduate students from 55 countries pursuing various master’s and doctoral programs. The Columbia Mailman School is also home to many world-renowned research centers, including ICAP and the Infection and Immunity Center. For more information, please visit

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