How to read a card

Every number carries a label that says how we know it, strongest first:

• filed Read from a published government file (NADAC, ASP, a fee schedule). Strongest.
• published From a payer's or provider's own published rate.
• derived Computed from a published rule (e.g. Medicare pays 80% of the fee schedule).
• estimated Inferred, with the reason recorded.
• stale The source file is older than its publisher’s schedule says it should be. The figure is still shown, never hidden or zeroed.

Under each number is its source line: the dataset, the exact file, the date the price took effect, the file’s own date and the date we downloaded it. “Sources and method” on the card opens every figure in full.