Every state is required to provide Medicaid coverage to certain groups: poor children and pregnant women, people with disabilities, and poor older people requiring long-term care. But the Obamacare expansion provides coverage for many poor parents and childless adults who were less often covered in the program. The health law provides federal funding for states to include all residents who earn below or just above the federal poverty line — the limit is about $16,000 for a single person.

In the first three years of the expansion, the federal government paid 100 percent of the tab. But now states need to chip in a small share to cover the expansion population’s medical bills. That share, 5 percent this year, is set to rise to 10 percent in 2020.

Some state governments and local think tanks have prepared estimates of the costs and benefits of Medicaid expansion in their region. But the Avalere analysis is the first to apply a consistent methodology across all of the states that have declined to expand. Some of the numbers are big. Florida would get an estimated $26 billion over the next decade, according to Avalere; North Carolina $13 billion.

The Medicaid expansion has been the subject of substantial scholarly attention. Strong evidence suggests states’ expansion has helped improve the financial health of their low-income residents, as well as the financial performance of local hospitals. Studies also show that Medicaid coverage has helped low-income Americans get access to health care, though there is not yet strong evidence about whether it has improved their physical health.