Health Insurance Marketplace 2015 Open Enrollment Period: December Enrollment Report. Section III. Methodological Overview


The data reported here have been obtained from the information systems of the Centers for Medicare & Medicaid Services (CMS), based on information collected for 37 states using the platform. We also obtained more limited data reported to CMS by the 14 states (including DC) that are using their own Marketplace platform. Data for the Small Business Health Options Program (SHOP) Marketplaces are not included in this report.

This report includes data that are currently available on enrollment-related activity for the first month of the open enrollment period – which generally corresponds with data from 11-15-14 to 12-15-14 for the 37 states, and from 11-15-14 to 12-13-14 for most of the states that are using their own Marketplace platforms for the 2015 coverage (see Table 4 below).

Table 4

Marketplace Type Reporting Period
States Using the Marketplace Platform (37 states) 11-15-14 to 12-15-14*
States Using Their Own Marketplace Platform (14 states)  
California 11-15-14 to 12-14-14
Other 13 States (including DC) 11-15-14 to 12-13-14

*Data for call center and website visits are for 11-15-2014 – 12-20-2014

Data for certain metrics are not yet available for several of the states that are using their own Marketplace platforms. Additionally, some states (Connecticut, Idaho, Kentucky, Vermont, and Washington) initiated automatic reenrollments prior to 12-14-2014; automatic reenrollments are included in these states’ plan selection data. This report does not include complete data on the number of individuals with 2014 Marketplace coverage who have selected health insurance coverage through the Marketplace that can begin on January 1, 2015 because the automatic reenrollments were not completed during the one-month period this report examines. In addition, some states extended their deadline for plan selection for January 1 coverage or offered special enrollment periods to consumers experiencing longer than normal wait times or other challenges.8 9

It is important to note that data for the 14 states that are using their own Marketplace platforms include new consumers but not all states are reporting reenrollments (California and New York are only reporting data for new consumers) and some states are not separately reporting data for new consumers and consumers who are reenrolling in Marketplace coverage. Most of the 14 states include activity through 12-13-14 (however data for California are through 12-14-14), ending prior to the surge associated with the deadlines for January 1st coverage.10 Please refer to Appendix C for additional technical notes.

This report also includes data on the characteristics of persons who have selected a Marketplace plan through the 37 states that are using the platform for 2014. In some cases, the data for certain characteristics of Marketplace plan selections are not yet available in selected states.

We believe that the information contained in this issue brief provides the most systematic summary of enrollment-related activity in the Marketplaces for the first month of the 2015 Open Enrollment period because the data for the various metrics are counted using comparable definitions for data elements across states and Marketplace types.

8 For example, in the states, the deadline for Marketplace coverage beginning on January 1st was 12-15-14. However, consumers in these states who experienced longer than normal wait times or other challenges as a result of increased website and call center activity near the December 15th deadline will be eligible for a Special Enrollment Period.

9 Dan Mangan, “More Extensions as Obamacare Deadline Looms,” accessed at

10 In the States that are using their own Marketplace platform, the deadline for Marketplace coverage beginning on January 1st varies. The deadline in the District of Columbia and Kentucky was December 15th, but some states have announced later deadlines. For example, the deadline in Maryland was December 18th; the deadline for Connecticut was December 19th; the deadline in New York and Idaho was December 20th; the deadline in California was December 21st; the deadline in Massachusetts and Washington was December 23rd; and the deadline in Hawaii, Minnesota, Rhode Island and Vermont is December 31st. Additionally, Connect for Health Colorado has offered to work with people who started the process before the December 15th deadline, but were not able to finish enrolling, to complete their application for January coverage.

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