Enrollment in Health Insurance

enrollment summaries

Monthly Enrollment Summaries
(through November 2020)

To provide more rapid insight into the impact of COVID-19 on insurance coverage in the Commonwealth, CHIA is now producing monthly enrollment data summaries by key market sectors. This new report series is in addition to CHIA's regular biannual Enrollment Trends reports.

This month’s publication includes enrollment figures through November 2020. CHIA intends to continue reporting on Massachusetts insurance coverage on a monthly basis as the impact of COVID-19 is further felt across insurance categories and market sectors.

Enrollment Trends

Enrollment Trends
(through March 2020)

Additionally, twice a year CHIA updates its detailed Enrollment Trends analysis for the most recent two-year period to give researchers and policymakers insight into the market. This edition covers the period between March 2018 and March 2020 and includes breakouts by payer and product type, providing a baseline for enrollment prior to the pandemic. The next Enrollment Trends publication will include detailed data through September 2020.

CHIA’s bi-annual Enrollment Trends reporting includes an interactive dashboard, a detailed databook, and technical appendix. For this reporting, coverage is defined by unique Massachusetts residents with primary, medical membership in the 12 largest commercial payers, MassHealth (Medicaid), or Medicare.

Enrollment measures are also reported in CHIA's Annual Report on the Performance of the Massachusetts Health Care System.


Updated September 2020

Previous Enrollment Publication Materials

2020 Publications

Monthly Enrollment Summaries







Enrollment Trends (through September 2019)
Published March 2020


2019 Publications

Enrollment Trends (through March 2019)
Published August 2019


Enrollment Trends (through September 2018)
Published February 2019


2018 Publications

Enrollment Trends (through March 2018)
Published August 2018


Enrollment Trends (through September 2017)
Published February 2018


2017 Publications

Enrollment Trends (through March 2017)
Published August 2017


Enrollment Trends (through September 2016)
Published March 2017


2016 Publications

Enrollment Trends (through March 2016)
Published July 2016


Enrollment Trends (through September 2015)
Published February 2016