The study finds that workers with highly variable weekly work hours, fluctuating annual incomes, or employment disruptions have far lower odds of having the option of getting health insurance coverage through an employer. These workers are more likely to be young, female, and to have low incomes than those with stable hours and incomes. Crucially, they are much more likely to rely on Medicaid or on health plans bought through the Affordable Care Act Marketplaces, compared with workers in the same income range who had more stable hours and incomes, who were more likely to be covered by an employer-sponsored plan. In other words, the workers least attached to traditional employment structures are precisely the ones filling the gaps left by an employer-first insurance system, and they are doing so through public programs and Marketplace plans that are now facing significant changes.

The timing of the research is significant. The results are being published just as 44 states prepare to require millions of Medicaid enrollees to document that they are working at least 80 hours per month, about 20 hours a week on average, or meeting other requirements, starting in 2027. Those who cannot document compliance will lose their coverage. The study suggests that workers with volatile work situations will be particularly susceptible to Medicaid disenrollment due to fluctuating hours and employment, even though they worked on average 33 to 35 hours per week, a figure very similar to the average for all low- and middle-income workers. In all, 70 percent of those with volatile hours had work schedules that fluctuated below 20 hours a week at some points during the year, meaning that even people who work substantial annual hours could fail a monthly reporting threshold during slow periods.

The study also comes at a time when the ACA Marketplace will see changes to eligibility, including those based on immigration status, and increases in costs for coverage in 2027. These changes follow the expiration of enhanced premium subsidies for 2026 plans. Marketplace enrollment for 2027 begins November 1 via healthcare.gov. Taken together, the researchers argue, the parallel shifts in Medicaid and Marketplace policy will disproportionately affect workers in volatile or unstable jobs, the very population that depends on these coverage pathways because employer-based insurance is out of reach.

Sumit Agarwal, M.D., M.P.H., Ph.D., the study’s senior author and an Assistant Professor at the U-M Medical School and School of Public Health, explained the structural logic behind the pattern. Low- and middle-income workers rely on those other forms of coverage because they cannot rely on access to employer coverage, he said, as companies outsource certain functions to contractors or hire more employees in roles that are not eligible for benefits. “They are the ones who will be hurt the most from changes in health policy that reduce access to the programs, such as Medicaid expansion and the ACA Marketplace, that were intended to fill in the gaps in the employer-first insurance system,” he said. “Millions of people are in those gaps.”

The researchers focused on people with incomes up to the level that qualifies for enrollment in Medicaid, particularly in states that expanded Medicaid to cover adults under 65 with incomes up to 138 percent of the poverty level. They also examined people with incomes up to 400 percent of the poverty level, the limit for some money-saving options on the ACA Marketplace. During the 2022-2023 period from which the study’s data came, an income at 400 percent of poverty would have been about $58,300 for a single person and $120,000 for a family of four. By 2026, the income cutoff for Medicaid enrollment in most states, 138 percent of poverty, is just over $22,000 for a single person and $45,500 for a family of four, while an income at 400 percent of poverty is $63,840 for a single person and $132,000 for a family of four. Alaska and Hawaii use different poverty levels.

Agarwal, who is both a general internal medicine physician at U-M Health and a health economist, said he has patients covered by Michigan’s Medicaid expansion program, the Healthy Michigan Plan, who are already very worried that their irregular work patterns will make it hard for them to meet the work requirements when they take effect next year. “Some of my patients are already anticipating that they will lose their coverage,” he said. “These are people who are working.” The specific requirements, and how states will implement systems for reporting or automatically tracking work or other activities, or granting exemptions based on health or other factors, will vary by state. A tracker is available from the Kaiser Family Foundation, and U-M Health is preparing to help patients understand how to navigate the requirements once they are known. For now, anyone covered by a Michigan Medicaid plan can check the state website for current information.

The methodological strength of the study lies in its longitudinal design. Agarwal and his colleagues, including lead author Vineeth Amba, M.D., M.P.H., a resident at Mount Sinai Hospital in New York, performed the study using data from the Medical Expenditure Panel Survey, a nationally representative survey run by the Agency for Healthcare Research and Quality. “A major advantage of the MEPS is that they interview people multiple times over two years, so we could identify which workers were in volatile versus stable work arrangements,” said Amba. “Workers in unstable jobs are a growing share of the low- and middle-income working population.” The researchers looked at how health insurance coverage and type were associated with measures such as income that varied more than 25 percent from 2022 to 2023, work hour volatility by week, and transitions from unemployed to employed.

The study sample comprised 1,621 people, and when the findings are extended to the whole US population, the scale of the phenomenon becomes striking. An estimated 14.6 million people had volatile incomes, compared with 10.6 million with stable incomes. Some 11.4 million had volatile hours, compared with 13.5 million with stable hours. And 2.9 million experienced an employment disruption, compared with 22.4 million having stable employment. These figures quantify, for the first time at a national level, how many working Americans face the kind of month-to-month unpredictability that can make both employer benefits eligibility and new administrative requirements difficult to satisfy.

The changes taking effect for Medicaid and the ACA Marketplace for 2027 stem from the federal budget bill signed into law in July 2025. At the time of the bill signing, Agarwal wrote about the changes in employment-based health insurance, and the experiences of Michigan and Arkansas in attempting to implement Medicaid work requirements, in a commentary for the nonprofit academic website The Conversation. The new study adds empirical weight to that argument, documenting that the workers most exposed to disenrollment under the new rules are not idle but are, on average, working nearly full-time hours in arrangements that simply do not offer steady schedules or benefits. In addition to Agarwal and Amba, the study’s authors are Renuka Tipirneni, M.D., M.Sc., and John Z. Ayanian, M.D., M.P.P., who like Agarwal are members of the faculty in the Division of General Medicine in the U-M Medical School Department of Internal Medicine. Ayanian directs, and Agarwal and Tipirneni are members of, the U-M Institute for Healthcare Policy and Innovation. As the 2027 deadlines approach, the study suggests that the design of state reporting systems, exemptions, and automatic tracking mechanisms will determine whether millions of working Americans keep or lose the coverage that fills the gaps their employers leave behind.

Subject of Research: The association between volatile employment and health insurance coverage among low- and middle-income American workers

Article Title: Study reveals the work & health insurance roller coaster millions of Americans ride

Article References: Study reveals the work & health insurance roller coaster millions of Americans ride. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: health insurance, Medicaid, ACA Marketplace, gig economy, work requirements, volatile employment, employer-sponsored insurance, low-income workers, health policy, JAMA Network Open, Medical Expenditure Panel Survey, coverage gaps