All states (including the District of Columbia) are required to provide data to the Centers for Medicare & Medicaid Services (CMS) on a range of indicators related to key Medicaid and Children’s Health Insurance Programs (CHIP) application, eligibility, and enrollment processes. These data reflect enrollment activity for all populations receiving comprehensive Medicaid and CHIP benefits in all states, as well as state program performance. CMS publicly releases these eligibility and enrollment data collected from states in monthly reports.
Preliminary & Updated Data
In Medicaid, people are potentially eligible for retroactive coverage for incurred health care costs dating back to 90 days before the date they applied. Also, states may not process all applications in the month they were received. To capture the most complete enrollment data possible, states report two types of data: preliminary and updated.
States report preliminary data approximately one week after the close of the reporting period. These data generally do not include retroactive enrollment or Medicaid- and CHIP-eligible people who applied during the reporting period but whose applications were not fully processed before the end of the month. Conversely, updated data is reported one month after the close of the reporting period and includes data for these two groups. CMS releases updated data for the previous month with each current monthly report.
Because updated data contains retroactive enrollments and preliminary data does not, the two types of data are not comparable. Only data of the same type should be compared across months (e.g., preliminary compared to preliminary). Note that many states continue to adjust their reporting methodologies to better align with CMS’s data specifications. The data context notes below and the state-specific notes in the report tables highlight these changes. In some cases, methodological changes prevent data of the same type from being perfectly comparable.
Baseline Enrollment Data
The monthly reports use the three-month period before the start of the initial Marketplace open enrollment (July through September 2013) as the baseline period. State baseline enrollment figures represent an average of their Medicaid and CHIP enrollment from July through September 2013. Baseline enrollment figures include updated data; therefore, comparing preliminary monthly data to the baseline slightly understates enrollment growth.
Prior Months’ Preliminary & Updated Reports
States update their preliminary data one month after the close of the reporting period to include any enrollment and eligibility activity not captured in their preliminary report. Updated data and prior month reports are available on the Monthly Medicaid and CHIP Application, Eligibility Determination, and Enrollment Reports and Updated Data page.