Massachusetts: Medicaid expansion enrollment up 25% since COVID hit; total Medicaid up 8%


I've once again relaunched my project from last fall to track Medicaid enrollment (both standard and expansion alike) on a monthly basis for every state dating back to the ACA being signed into law.

For the various enrollment data, I'm using data from's Medicaid Enrollment Data Collected Through MBES reports. Unfortunately, they've only published enrollment data through December 2020. In some states I've been able to get more recent enrollment data from state websites and other sources.

Today I'm presenting Massachusetts. For enrollment data from January 2021 on, I'm relying on adjusted estimates based on raw data from the Massachusetts Health Dept. (MassHealth).

The Medicaid expansion situation in the Bay State is a bit unusual for two reasons: First, MA is one of only two states (besides Vermont) in which every ACA expansion enrollee was already eligible for the program prior to the ACA via previously-enacted legislation or federal waivers. For these states, the only significant change is that 90% of the cost of covering this population is now paid for by the federal government instead of the state.

In addition, as the graph shows, unlike most states, according to the official MBES data, Massachusetts' traditional Medicaid population has jumped around quite a bit over the past 8 years, spiking at the end of 2014, then dropping sharply a few months later, then seeing a couple of odd one-time dips & spikes in late 2017/early 2018...and then finally seing an oddly sharp drop in January 2019 before jumping back up again a few months later. Huh.

Since the COVID pandemic hit last February, MA's non-ACA Medicaid enrollment has only increased slightly (4.1%), but their expansion population went up by a full 25%, for an overall increase of 8.2%.

Massachusetts has 7,029,917 residents according to the 2020 U.S. Census. As of February 2021:

  • around 1.83 million are enrolled in Medicaid overall, or 26% of the population
  • around 1.42 million are enrolled in non-ACA Medicaid
  • around 412,000 are enrolled in ACA Medicaid expansion.
  • Add in the ~198,000 subsidized ACA exchange enrollees and that's around 610,000 Bay Staters who would lose healthcare coverage if the Supreme Court strikes down the Affordable Care Act, or 8.7% of the state population. While you might think that the expansion population would simply revert back to their pre-ACA status, that assumes that the state still has the funding to pay for them to do so. In most states which have a "previously eligible" population, that funding source has long since been discontinued, which means those 412K folks would be in the same boat as the newly-eligible enrollees in other states.