Methodology and source ledger
Sources
Every number on this site comes from CMS public use files: the annual Medicare Advantage/Part D landscape file (premiums, county availability, star ratings), the Plan Benefit Package (PBP) benefit files (cost sharing and supplemental benefits as bid and approved), the plan crosswalk (year-over-year plan lineage), and the Medicare Plan Finder benefit summary, plus the Monthly Prescription Drug Plan Formulary and Pharmacy Network Information file (Part D formularies, tier cost sharing, PDP plan list and regions, and the pharmacy-network tables — which retail and mail-order pharmacies are in each plan's network and which are preferred; names, addresses and phone numbers come from the CMS NPPES NPI registry and distances from Census 2020 ZIP code (ZCTA) centers). No plan, carrier, or agency supplies or edits any figure.
Drug names, ingredients and brand names come from RxNorm (Current Prescribable Content), matched on the RxCUI codes in the CMS file. This product uses publicly available data from the U.S. National Library of Medicine (NLM), National Institutes of Health, Department of Health and Human Services; NLM is not responsible for the product and does not endorse or recommend this or any other product. Formularies are filed per formulary ID and shared by many plans; coverage counts on drug pages are counts of formularies, not plans. Tier cost sharing shown is the initial-coverage amount for a 30-day retail or 90-day mail supply as filed; deductibles, the annual out-of-pocket cap, the insulin cap and negotiated prices apply on top. The CMS file is monthly; the site is rebuilt when a new month posts.
Source ledger for this release
Scope and exclusions
Scope is individual Medicare Advantage plan segments, identified by contract ID, plan ID and segment ID. Employer-group (800-series) plans, PACE, demonstrations, and stand-alone Part D plans are excluded from counts. A plan segment is one row in the PBP; a county-plan filing is one plan segment available in one county, so a plan filed in 48 counties contributes 48 filings.
How values are represented
Yes/No benefit indicators reflect the plan's approved bid. — means CMS did not publish a value for that field, which is not the same as No. Reported under an allowance means the benefit is offered with no published amount. Benefit counts are plan-segment counts and are not weighted by enrollment. "Minimum reported" copays are the lowest amount in the bid for that service category. Star ratings are the overall contract rating in the CMS file in effect at build time.
Refresh cycle
CMS posts the landscape file in late September, updates Plan Finder on October 1, and posts PBP benefits roughly three weeks later. Each release is downloaded, hashed, loaded into a versioned DuckDB warehouse, validated against the prior year's counts, and republished here; the ledger above records what went into this build.