Data Note: Changes in Enrollment in the Individual Health Insurance Market through Early 2019
First quarter enrollment is generally higher than average annual enrollment, because people drop coverage throughout the year after the annual open enrollment period. In this brief, we compare first quarter 2019 enrollment to first quarter enrollment in previous years to estimate how enrollment is changing over time.
Estimates of the size of the individual market vary between administrative and survey data; a more thorough discussion of methods for measuring the individual market size can be found here.
ACA changes came into effect in 2014, but 2014 average enrollment is not necessarily comparable because the first open enrollment lasted for 6 months.
Exchange enrollment is measured as the number of enrollees who selected a plan during open enrollment and paid their first month’s premium (effectuated enrollment). In 2014, open enrollment lasted for six months and CMS did not report effectuated enrollment in the first quarter. In 2015 and 2016, CMS reported effectuated enrollment as of March 31st. In 2017, 2018, and 2019, CMS reported effectuated enrollment as of March 15th, and did not include policies starting on March 1st. Open enrollment for 2017 continued through the end of January, but for the 2018 and 2019 plan years it ended on December 15. It is likely, therefore, that effectuated enrollment for 2017 was somewhat understated relative to 2018 and 2019.
For 2015 through 2018, we assume the share of off-exchange enrollment in compliant plans in Q1 is the same as the share of annual enrollment in off-exchange compliant coverage. Data on the share of off-exchange enrollment in compliant plans in 2019 are not available, so it is assumed to be the same as the share in 2018.