Visualizing LIS Eligibility
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Visualizing LIS Eligibility


The Medicare Part D Low-Income Subsidy (LIS/Extra Help) is a valuable resource for Medicare beneficiaries with limited means to afford their prescriptions.

Yet many people with Medicare remain unaware of and unenrolled in LIS. This mapping tool enables benefits counselors to find information on these individuals potentially eligible for but not enrolled in LIS down to the zip code level.

How to use this graphic

Zip codes colored blue are those areas likely to have unmet need for enrollment in LIS/Extra Help. The darker the shade of blue, the larger the percentage of Medicare beneficiaries in the zip code who are estimated to be eligible but not enrolled in the subsidy.

Zip codes shaded gray are unlikely to have a high degree of unmet need. That’s not to say there’s no one who’s eligible but not enrolled in these localities, especially with 10,000 people a day in the United States aging into Medicare and needing help getting into benefits for which they may qualify – and, as noted below in the data sources, these are underestimates.

Mousing over a bubble or zip code will provide more information about the corresponding area. Zoom controls for the map will appear in the upper left when you mouse over the map. In addition, you may pan the map by holding both mouse buttons and dragging.

Data sources

Enrollment data for LIS was crosswalked from county-level data as of March 2014 (available through CMS at, while potential eligibility is estimated as Medicare beneficiaries below 150% FPL via the 5-year sample of the 2013 American Community Survey (ACS).

This methodology results in an underestimation for a number of reasons. First, the ACS is an estimate itself while the enrollment data are actual rolls. Second, the later enrollment data means that demographic change (i.e. growth of Medicare beneficiaries) in the potential number of eligibles over the intervening years goes uncaptured. Finally, while 150% FPL is the cut-off for LIS eligibility, this does not take into account deductions which allow incomes over 150% FPL to qualify. On the other hand, it does not take into account assets which may render people who are otherwise eligible based on income ineligible due to net wealth exceeding the limit, so this may be a wash.

As such, the data should be seen as estimates only.

Questions about the map may be directed to Conor McGovern, Senior Research Associate for Economic Security, at