Press Releases
October 20, 2020

Revised CMS Figures Show Medicare Advantage Surpassing 40% of Medicare Enrollment

Updated data corrects past reporting discrepancy 

Washington, D.C. – Better Medicare Alliance (BMA), the leading research and advocacy organization supporting Medicare Advantage, responded to new data from the Centers for Medicare & Medicaid Services (CMS) showing that Medicare Advantage penetration has exceeded a milestone of 40% of the total Medicare-eligible population nationwide.

The findings were released in CMS’s October 2020 “MA State/County Penetration” monthly report. The report shows 25,389,561 Medicare Advantage beneficiaries nationwide for the month of October out of a Medicare-eligible population of 62,462,094 individuals. This results in a Medicare Advantage penetration rate reached an all-time high of 40.6%.

Earlier releases of the Medicare Advantage penetration data, including in the month prior, indicate a Medicare Advantage penetration rate of 36.2%. The change in the numbers was the result of Better Medicare Alliance having identified discrepancies in the data and requesting a CMS review to address these possible inaccuracies in the numbers and resulting percentage of penetration. CMS was responsive and made corrections to the data file, leading to a significant increase in the penetration rate for Medicare Advantage due to an overcounting of Medicare beneficiaries since 2017. 

“With Medicare Advantage set to enroll nearly 27 million Americans this fall, we’ve long known that seniors are increasingly making an active choice for the lower costs, better care coordination, and improved health outcomes uniquely found in Medicare Advantage. These updated CMS figures – reflecting a key correction first requested by Better Medicare Alliance – paint a clear picture of the progress made in Medicare Advantage meeting the preferences and needs of Medicare beneficiaries. We now know that Medicare Advantage has officially exceeded 40% of the total Medicare population, and likely met this milestone benchmark some time ago,” said Allyson Y. Schwartz, President and CEO of the Better Medicare Alliance. “We thank CMS for their swift review and correction to the data following BMA’s initial outreach and want to acknowledge the significance of these new numbers, as they indicate the growth in enrollment and the meaningful role of Medicare Advantage for the millions of beneficiaries it serves. With more than 40% penetration nationwide, Medicare Advantage continues to earn the trust of older Americans and cement its place in the Medicare success story.”


Each month, CMS publishes data files detailing enrollment numbers and service areas for Medicare Advantage and Prescription Drug Plans. One of the files published, “MA State/County Penetration” provides data on the share of Medicare beneficiaries that are enrolled in Medicare Advantage at the state and county level.

This year, as Better Medicare Alliance was updating BMA’s Medicare Advantage Enrollment Map for 2020, discrepancies were identified with the Medicare Advantage penetration rates compared to similar figures published by the CMS Office of the Actuary and the CMS Enrollment Dashboard. Specifically, the number of total Medicare beneficiaries was much higher in the “MA State/County Penetration” file than in the other sources, while the total MA enrollment was similar. The result of these differences was a lower estimated rate of Medicare Advantage penetration using the CMS “MA State/County Penetration” file compared to other sources.

For example, earlier this year, the “MA State/County Penetration” file indicated there were 67.8 million beneficiaries eligible for Medicare, while the other sources indicated 61.2 million beneficiaries. This discrepancy results in a difference in penetration rates of 36.6 percent when using the “MA State/County Penetration” file and 40.0 percent when using other sources.  Upon further evaluation, we discovered that this discrepancy first started in 2017.

In June, BMA engaged CMS staff to share our findings and ask the Agency to investigate the discrepancy. Following our discussion, CMS reviewed their enrollment data, acknowledged an error, and indicated that the Agency would update the “MA State/County Penetration” file to ensure the data was accurate.

On October 19, 2020, CMS published the October “MA State/County Penetration” file with a note of explanation that an issue was identified in previous files in which the number of beneficiaries with multiple addresses was being counted twice. CMS has also committed to correcting the files going back to 2017.

View the CMS October 2020 MA State/County Penetration file HERE.


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