How KnowYourPrime Works
What counts as evidence here, how a confidence rating is computed from it, and what this site will not tell you.
What goes in
Peer-reviewed studies, systematic reviews, meta-analyses, and clinical guidelines. Manufacturer documentation is used for one narrow purpose: describing what a device claims to do and display, never as evidence that it does so accurately. The accuracy ratings on this site come from independent research. Every metric has its own Research Desk, a dated file of which studies inform each claim.
What never goes in: anecdotes, marketing claims, unsourced health advice, or forum posts presented as evidence. Forums show what people are asking. They are never a source.
A worked example: how a confidence rating gets computed
Take an actual claim currently on the VO2 Max Research Desk: "Consumer wearable devices estimate VO2max accurately enough to be meaningful."
Seven studies are tracked against this claim: four treated as anchor-grade evidence (the strongest tier a claim can rest on here), three as supporting evidence.
- One anchor affirmsA Garmin validation study found acceptable agreement against lab-based reference testing.
- Three anchors don’t cleanly affirmAn Apple Watch study and a multi-tracker study both found accuracy below the bar for close agreement. A Google Pixel Watch 3 study found the average close to the lab value, but individual readings spread from about 12.6 mL/kg/min below it to 11.5 above (95 percent limits of agreement).
- The ruleTwo independent affirming anchors are required to reach the top tier. One clean affirming anchor isn't enough on its own, no matter how strong that one study is.
Result: the claim is rated Emerging, meaning the evidence currently favors the claim but more confirmation is needed. You can see this claim, its rating, and every study behind it on the VO2 Max Research Desk. The same rating is recorded as Finding KYP-ER-0011 in the KnowYourPrime Evidence Registry, the permanent, citable record of each rated question, with a fixed ID and a dated version history.
What this site cannot do
It cannot diagnose disease, replace a clinician, or know anything about your individual health. It cannot determine whether a published study is itself correct: it reports what studies found, it doesn't re-run their statistics. It cannot detect fraud in a source paper. And it cannot guarantee today's rating survives tomorrow's evidence: ratings are dated and revised, not fixed forever.
Corrections
When an error is found, in a source, in a claim, or in how something was worded, the page is corrected. Corrections that change a finding are dated on the page itself.
Last updated: October 2026