Purpose and Scope
There is no single source for Medicare enrollment statistics. Various sources described in this report present different breakdowns of enrollment data, including coverage type (Parts A, B, C, and D), beneficiary type (aged, disabled), and geographic area. This report provides guidance in determining the most current sources for different categories of enrollment data.
The report presents basic categories and definitions for terms related to Medicare enrollment data, a quick reference table that summarizes key data available in selected resources, and a more detailed overview of core resources.
Categories and Definitions
This section provides basic definitions of Medicare coverage and beneficiary types in order to aid users in identifying the most useful sources for their questions. Because different sources may use a variety of terms and abbreviations to refer to the same data, this section also includes commonly used synonyms for different types of Medicare coverage.
For more background information on Medicare, please see CRS Report R40425, Medicare Primer, coordinated by [author name scrubbed].
- Total Enrollment: Includes all beneficiaries (aged and disabled) and all Medicare parts (A, B, C, D).
- Enrollment in (Geographic Area): National, state, territory, county, or congressional district.
- Enrollment for (Beneficiary Type): Beneficiaries become eligible for Medicare based on age or disability.
- Enrollment in (Type of Coverage): Beneficiaries may be enrolled in more than one part of Medicare. Most persons aged 65 or older are automatically entitled to premium-free Part A based on their payment of Medicare payroll taxes, whereas other parts are voluntary.
• Part A: Provides coverage for inpatient hospital services, posthospital skilled nursing facility (SNF) services, hospice care, and some home health services. May be referred to as HI (hospital insurance).
• Part B: Provides coverage for physicians' services, outpatient hospital services, durable medical equipment, and other medical services. Beneficiaries voluntarily enroll and pay premiums. May be referred to as SMI (supplementary medical insurance).
• Original Medicare: Refers to Parts A, B, or both. Also called FFS (fee-for-service).
• Part C: Private insurance option that combines Parts A and B coverage. Also called MA (Medicare Advantage), Medicare Managed Care, or formerly Medicare+Choice.
• Part D: Provides coverage of outpatient prescription drugs through optional enrollment and premium payments. May be provided through private prescription drug plans (PDPs) or through Medicare Advantage prescription drug plans (MA-PDs).
- Dual-Eligible Enrollment: Individuals who qualify for both Medicare and Medicaid. These enrollees may be aged or disabled beneficiaries, and may qualify for full or partial Medicaid benefits. Also called dual enrollment.
- Medigap Enrollment: Beneficiaries can optionally enroll in private individual insurance policies that supplement original Medicare. These plans are standardized and identified by plan letter (Plans A-N). Also called Medicare Supplemental Insurance.
Selected Sources for Medicare Enrollment Statistics
This section provides detailed information on core sources for Medicare enrollment statistics and includes links to each source. Table 1 summarizes key data available in selected sources.
Table 1. Selected Sources for Medicare Enrollment Statistics
("+" indicates the statistic is included in the source; "—" indicates the statistic is not included in the source.
Click on each source to navigate to full details in the report.)
|
Source |
Coverage Type |
Geographic Area |
Beneficiary Type |
Currency |
|||||||||
|
A |
B |
C |
D |
Original Medicare (A and/or B) |
National |
State |
Territorya |
County |
Cong. District |
Aged |
Disabled |
||
|
— |
— |
+ |
+ |
+ |
+ |
+ |
AS, GU, NM, PR, VI |
+ |
— |
— |
— |
Delay of 2-3 months |
|
|
+ |
+ |
+ |
+ |
+ |
+ |
— |
— |
— |
— |
+ |
+ |
Previous year |
|
|
+ |
+ |
+ |
— |
+ |
+ |
+ |
AS, GU, NM, PR, VI |
— |
— |
+ |
+ |
Irregularb |
|
|
— |
— |
+ |
+ |
+ |
+ |
— |
— |
— |
— |
+ |
+ |
Previous year |
|
|
+ |
+ |
— |
— |
+ |
+ |
+ |
PR, VI |
+ |
— |
+ |
+ |
No longer updatedc |
|
|
— |
— |
+ |
+ |
— |
— |
+ |
AS, GU, NM, PR, VI |
+ |
— |
— |
— |
Delay of 1 month |
|
|
— |
— |
+ |
+ |
+ |
+ |
+ |
PR, VI |
+ |
+ |
— |
— |
Irregulard |
|
Source: Compiled by the Congressional Research Service (CRS).
Notes: Not all data sources in this report are represented in this table. For information on topics such as dual-eligible populations and Medigap, see the full report.
a. Territory abbreviations: American Samoa (AS), Guam (GU), Northern Mariana Islands (NM), Puerto Rico (PR), and Virgin Islands (VI).
b. This source was last updated with CY2013 data.
c. This source was last updated with CY2012 data but remains the only publicly available source for county-level data on Part B enrollment and breakdowns of aged and disabled beneficiary populations.
Centers for Medicare & Medicaid Services
The Centers for Medicare & Medicaid Services (CMS) is part of the Department of Health and Human Services (HHS) and administers programs such as Medicare, Medicaid, the Children's Health Insurance Program (CHIP), and the Health Insurance Marketplace. CMS sites and reports are the primary sources for Medicare enrollment data.
Medicare Enrollment Dashboard
Based on CMS administrative data, this resource provides monthly enrollment numbers for the most recent 12 months and annual data since 2011. Maps and charts (see Figure 1 for an example) are created according to user selections such as geographic areas (national, state, county) or coverage type (Hospital/Medical by Original Medicare, Medicare Advantage and Other, Total, and Prescription Drug). Note that this source does not provide breakdowns by aged or disabled beneficiaries, Part B, or congressional district.
 |
|
Source: Centers for Medicare & Medicaid Statistics. |
Medicare Enrollment Reports
An alternative CMS data source, Medicare Enrollment Reports, includes more granular data not currently available through the "Medicare Enrollment Dashboard." Most importantly, this is the only source to provide enrollment information by county for Part B and aged or disabled beneficiaries. The most recent data in this format are from July 2012. These tables break down enrollment by state, and then distinguish among enrollment in Part A and/or B, A only, B only, and A and B. Additionally, some of these reports limit to beneficiary type (i.e., aged or disabled) or both aged and disabled by state and county.
The reports include the following tables:
- "Medicare Enrollment: All Beneficiaries, July 2012," at https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/MedicareEnrpts/Downloads/12All.pdf;
- "Medicare Enrollment: Aged Beneficiaries, July 2012," at http://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/MedicareEnrpts/Downloads/12Aged.pdf;
- "Medicare Enrollment: Disabled Beneficiaries, July 2012," at https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/MedicareEnrpts/Downloads/12Disabled.pdf; and
- "Medicare Enrollment: Aged and Disabled by State and County, July 2012," at https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/MedicareEnrpts/Downloads/County2012.pdf.
Congressional District Report
https://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovGenIn/index.html
This source provides July 2016 enrollment by congressional district for Original Medicare, Part C, Part D, and Medicare Retiree Drug Subsidy.
To view these data, go to the Prescription Drug Coverage page and download the "2016 Congressional District Report" zip file, found at the top of the "Downloads" section. Open the first file (entitled "1_2016 Congressional District Report.xlsx"). Navigate the tabs to access MA (Part C), FFS (Original Medicare, i.e., Part A and/or Part B), and Part D enrollment for each congressional district. The data are organized by state and include state totals.
Medicare Advantage/Part D Contract and Enrollment Data
This site provides detailed information on Part C and Part D, including enrollment in specific plans or plan types (HMO, PPO, MSA, etc.) by state and county. This information is current with a one-month lag, compared to a two- to three-month lag on the "Medicare Enrollment Dashboard." Please note that data are accessible through Excel files and require some manipulation.
CMS Program Statistics
This portal links to CMS administrative data on Medicare enrollment since 1985, including annual trends, demographic breakdowns, maps, state tables, enrollment in Medicare Advantage and other health plans, newly enrolled beneficiaries, Medicare deaths, and Medicare-Medicaid dual enrollment. The most recent data are for 2013. This replaces but still refers to the Medicare and Medicaid Statistical Supplement, which was published from 2001 to 2013. For earlier statistics, see the "Historical Enrollment Data" section.
CMS Fast Facts
This quick reference statistical summary on annual CMS program and financial data includes a simple table with national enrollment data on Medicare and Medicaid.
Medicare-Medicaid Coordination Office: Analytic Reports and Data Resources
This portal links to several reports with enrollment data for dual-eligible Medicare-Medicaid beneficiaries. These include annual reports to Congress, the State Data Resource Center, and analytic reports addressing national, state, and county-level data trends.
CMS Office of Legislation Contact Information
https://www.cms.gov/About-CMS/Agency-Information/CMSLeadership/Office_OL.html
For more information on Medicare enrollment data, congressional staff members may directly contact the CMS Office of Legislation. The CMS Congressional Affairs Group Director is Maria Martino (202-690-8220, [email address scrubbed]).
Medicare Board of Trustees
The Medicare Board of Trustees has six members. Four serve based on their positions in the federal government: the Secretary of the Treasury, the Secretary of Labor, the Secretary of Health and Human Services, and the Commissioner of Social Security. The two other members are public representatives. These members oversee financial operations of the Hospital Insurance (HI) and Supplementary Medical Insurance (SMI) trust funds. The board, working with the CMS Office of the Actuary, prepares a report each summer.
Medicare Board of Trustees Annual Report
The Trustees Report includes national enrollment trends and projected enrollment by part (A, B, C, D). The report also includes breakdowns of Part D enrollment by subsidy type and ratios of Part C to total Medicare enrollment. Specific enrollment tables for the most recent report include the following:
- "Table II.B1. Medicare Data for Calendar Year 2015" (p. 10 of the 2016 Annual Report): includes general enrollment breakdowns by part (A, B, D), beneficiary type (aged, disabled), and in total.
- "Table IV.B7. Part D Enrollment" (p. 145 of the 2016 Annual Report): includes both enrollment statistics and projections for 2006-2025. Also includes breakdowns of enrollment by subsidy type.
- "Table IV.C1. Private Health Plan Enrollment" (p. 156 of the 2016 Annual Report): includes Part C enrollment and projections for 2006-2025. Also includes ratios of Part C to total Medicare enrollment.
- "Table V.B4. Medicare Enrollment" (p. 186 of the 2016 Annual Report): includes enrollment statistics and projections for 1970-2090 by part and in total.
Medicare Payment Advisory Commission
The Medicare Payment Advisory Commission (MedPAC) is a nonpartisan legislative branch agency that provides Congress with analysis and policy advice on the Medicare program and provides reports on specific Medicare-related topics.
MedPAC Reports
http://www.medpac.gov/-documents-/reports
MedPAC issues two standard reports to Congress each year. The Medicare Payment Policy report is released in March, and the Medicare and the Health Delivery System report is released in June. Basic chapters are consistent each year, but others reflect policy areas of interest and mandated reports. Additional stand-alone reports are sometimes issued as required by Congress or at the direction of MedPAC.
In some chapters, enrollment data from the Medicare Board of Trustees Annual Report or CMS enrollment files are presented and accompanied by analysis. Within the most recent Medicare Payment Policy report, the Medicare Advantage (Part C) chapter provides enrollment tables.
Data Book: Health Care Spending and the Medicare Program
http://www.medpac.gov/-documents-/data-book
This portal provides access to the most recent tables and graphs describing the Medicare program, including enrollment by beneficiary demographics.
America's Health Insurance Plans
America's Health Insurance Plans (AHIP) is the health insurance community's national trade association. As an advocacy group, it compiles statistics and issues reports.
CMS does not track Medigap enrollment, but AHIP provides two reports on this topic.
Trends in Medigap Enrollment and Coverage Options
https://www.ahip.org/wp-content/uploads/2017/05/Medigap_Report_5.1.17.pdf
Based on December 2015 data from the National Association of Insurance Commissioners (NAIC), this report provides information on Medigap enrollment by plan (A-N) and state/territory.
Beneficiaries with Medigap Coverage
https://www.ahip.org/wp-content/uploads/2016/01/MedigapDemoReport_1.15.16_2.pdf
Based on 2013 data from the Medicare Current Beneficiary Survey (MCBS), this report provides demographic analysis of beneficiaries enrolled in Medigap policies. Demographic factors include age, urban/rural area of residence, and income range.