Methodology & data sources

Transparency is the core of our E-E-A-T: this page documents exactly where our data comes from, what each figure means, how we compute derived values, and the limitations you should keep in mind.

Primary data source

All figures come from the official CMS Medicare Part D Spending by Drug annual dataset, published by the U.S. Centers for Medicare & Medicaid Services (CMS) on data.cms.gov. It is a U.S. government work in the public domain. We use the latest annual file (data year 2023, CMS release year 2025 (published May 2025); CSV DSD_PTD_RY25_P04_V10_DY23_BGM.csv), which reports each drug for years 2019–2023. We use 2023 as the latest year and 2022 for year-over-year comparisons.

Data snapshot as of June 2026. CMS releases this file roughly annually; we refresh when a new data year is published.

What each figure means

• Total spending — gross drug cost (Medicare, plan and beneficiary payments combined) across all Part D claims for the drug that year. It is not a list price, a negotiated price, or the net price after confidential manufacturer rebates.
• Spending per dosage unit — total spending divided by total dosage units (pills, tablets, mL, grams), volume-weighted across formulations.
• Spending per claim — average gross cost of one filled prescription.
• Spending per beneficiary — total spending divided by the number of unique beneficiaries who used the drug.
• Claims / beneficiaries — number of prescription fills, and number of distinct people, that year.

Derived values

• Total-spend year-over-year is computed by us as (spending 2023 − spending 2022) / spending 2022.
• Per-dosage-unit change and the 2019–2023 CAGR are taken directly from the CMS fields (Chg_Avg_Spnd_Per_Dsg_Unt_22_23 and CAGR_Avg_Spnd_Per_Dsg_Unt_19_23).
• National spend rank is the drug's position among all 3,598 drugs by total 2023 spending (1 = highest).
• Each drug uses the CMS Overall manufacturer-aggregate row. Manufacturer hub rollups attribute a drug's spending to its primary listed manufacturer and are indicative, not definitive.

Coverage

The CMS file lists about 3,598 drugs for 2023. We publish a full detail page for the 350 highest-spend drugs (which together account for the large majority of total program spending) and list the remaining long tail inside the ranking tables. We expand the published set in later waves based on search demand rather than padding with thin pages. Where CMS suppressed or omitted a value, we render an em dash (—) or "N/A" and never invent it.

Limitations & important note

These are aggregate public-spending figures, not the price you pay. Total spending is gross of confidential rebates, so it overstates the program's net cost. Per-unit and per-beneficiary averages can be skewed by low-volume specialty drugs. Figures are a static snapshot and may lag the source. Nothing here is medical, financial or pricing advice. Your out-of-pocket cost depends on your specific Part D plan, deductible and coverage phase — verify with your plan and a pharmacist. Always check the primary CMS source before relying on a number. See our disclaimer.

Last updated: 2026-06-21