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Administration for Community Living 

Tip Sheet 

Medicare Advantage Penetration Analysis 

Purpose: 

Community Based Organizations (CBOs) engaging in contracting with Managed Care 

Organizations should have a detailed awareness of the penetration of Medicare Advantage plans 

(also called Medicare health plans) in their particular market. The Centers for Medicare & 

Medicaid Services (CMS) provides monthly data on Medicare Advantage (MA) penetration in the 

United States. This tip sheet provides an overview of how to access and use that data to conduct 

a market analysis. 

Background: 

Medicare Advantage, also known as Medicare Part C, provides an option for Medicare 

beneficiaries to enroll in a managed care plan to administer their Medicare benefit. If a CBO 

wishes to provide reimbursable services to a beneficiary enrolled in a Medicare Advantage plan, 

then the organization must contract directly with the Medicare Advantage plan before initiating 

services for the target population. 

Accessing the Data: 

1. First, access the CMS website (shown in screenshot below) dedicated to providing Medicare 

Advantage (Part C) and Medicare Part D enrollment data using the following web link: 

https://www.cms.gov/MCRAdvPartDEnrolData/01_Overview.asp#TopOfPage

2. On that webpage you will see a series of options along the left side of the page. In order to 

determine how many beneficiaries in your service area are enrolled in Medicare Advantage 

plans, you need to click on the “MA State/County Penetration” link on the left hand side (see 

the arrow in the below screenshot). 
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Administration for Community Living 

3. After you click on “MA State/County Penetration”, you will see a listing of available files, 

categorized by “Report Period” (year, then month). See screenshot below: 

4. Identify the year and month for which you want to view Medicare Advantage enrollment 

data. Click on that link. 

5. After you click you will see a link to download a zipped CSV File. Click on that link and when 

prompted, accept the request to download the file. 
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Administration for Community Living 

6. Open the downloaded file. 

7. Note: It is a large file and the data in the file is categorized in alphabetical order by state and 

then by county. 

8. Scroll to the state and then the county that you wish to analyze. 

9. Scroll across the table to determine the key data elements for the market you are analyzing. 

Key data elements include the following: 

a. Eligibles: Universe of Medicare beneficiaries in that county in Original (fee-forservice) Medicare and in Medicare Advantage plans 

b. Enrolled: Number of eligible beneficiaries in that county who have enrolled in a 

Medicare Advantage plan 

c. Penetration: Percentage of Medicare beneficiaries in that county enrolled in MA 

plans 
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Administration for Community Living 

In order to get the number of Medicare beneficiaries enrolled in Original Medicare, subtract 

the number of Enrolled from the number of Eligibles. (See example below.) 

10. Example: 

Essex County, MA (September 2014) 

• Eligibles (Total Number of Medicare Beneficiaries) = 140,377 

• Enrolled (Total Number enrolled in an MA Plan) = 24,970 

• Penetration = 17.79% 

• Total Number of Medicare Beneficiaries enrolled in Original Medicare = 140,377 –

24,970 = 115,407 

Why Use This Data? 

Analyzing this data can help you figure out your target market for services your 

organization/network may wish to market and sell. Medicare beneficiaries enrolled in a 

Medicare Advantage plan have their benefits covered by that plan. Medicare beneficiaries not 

enrolled in an MA plan have their benefits covered by Original Medicare. If your 

network/organization wants to provide services under Medicare Part B (such as Diabetes SelfManagement Training, or DSMT) and be reimbursed by Medicare, then your potential target 

population would be the number of Medicare beneficiaries who are not enrolled in an MA plan, 

which is Eligibles – Enrolled. Using the example above, the number of beneficiaries who would be 

included in the target population, as of August 2014, is 114,495. 
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Administration for Community Living

In addition, low MA Plan penetration might also correlate with higher Accountable Care 

Organization (ACO) activity in a given market. Only Medicare beneficiaries in traditional 

Medicare can participate in an ACO, which might lead your organization toward marketing your 

services to ACOs in your area. Similarly, high MA penetration might point you toward marketing 

your services toward MA plans in your area.