How we verify

Primary means the entity that sets the number: the FDA label, the guideline document, the agency's fee schedule, the manufacturer's own price page, the peer-reviewed paper. Trackers, aggregators, news reports and other publishers are useful for finding a primary source and are never cited for a number. If the only source is an aggregator, the number is marked unverified or cut.

A price, a threshold or a recommendation can be correct as published and wrong today. Reference-range rows and screening rows print the source's effective date; prices on reviews are printed as of the date we read them; guides state when they were last checked.

A citation is verified only when someone has read the source's title and text against the specific claim it supports. A link that resolves proves only that the page exists. We re-probe every external link before publishing and again when a page is updated; a dead citation is removed rather than left.

Laboratories print different reference intervals and guideline bodies set different targets. Rather than blend them into one number, the Biomarker Library shows each as its own row with its own source: a lab interval is labelled as a lab interval, a treatment threshold as a threshold, and where a guideline target differs from a lab's normal range we say so.

A count or a rate derived from our own database is published only after we have measured how complete that database is. A gap in our records reads exactly like a gap in the world, so we do not present one as the other.

Before a product or service can be linked, we run it against FDA warning letters and import alerts, state board and attorney-general actions where the operating entity is named, and, for sellers of compounded medicines, their own disclosure that the products are not FDA-approved. The date of the check is recorded and published on how we pick. A partner without a recorded check cannot render a link; the software enforces it.

"Unverified", "the publisher gives no total" and "we could not source this" are all acceptable on this site and all better than a confident wrong number. Where we compute a figure rather than read it, we label it as our arithmetic and show the components.

• Can I point at the sentence that says this?
• Is this the whole thing, or one line of it?
• Does the publisher actually publish the aggregate I want, or am I manufacturing it?
• Was this ever operative, or is it a plan?
• Does "covered" mean paid for the thing the reader thinks?
• Has the scheme changed, not just the amount?
• Is there a single value, or must I name a tier?
• Does my provenance label certify the specific claim, or merely that the document exists?