Reference · How this site cites

Evidence Grading and Sources

Every reference page on this site states where its content comes from and how strong that source is. This page explains the rules used to decide.

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Veterinary review pending. This page describes a documentation convention. It is not a clinical guideline and it does not upgrade any claim made elsewhere on the site.

Start with the conclusion

Reference pages on this site are written from a working source list. Every source is assigned a level from A to D, and the level determines what the source is allowed to support in the text. The purpose is to keep three things apart: what a peer-reviewed study shows, what a professional organisation publishes, and what a vendor or marketplace page states.

The grading levels

LevelWhat belongs hereWhat it can supportWhat it cannot support
ASpecialty organisations, university hospitals, peer-reviewed papers (full text verified)Descriptions of clinical principles, reported findings with sample sizes, evidence boundariesClaims about a specific commercial product's performance
BCase series, reviews, technical material, sources with clear provenance but limited strengthDirectional findings, mechanism explanations, practice pointsEffectiveness claims or incidence figures
CVendor pages, marketplace listings, community content, search snippets, unverified leadsDescriptions of how products are priced, specified and deliveredClinical effectiveness or safety conclusions; public promotion
DUnverified, unsourced or conflated materialNothing on its own; it is a lead to verifyAny published claim

Two rules that follow from the levels

How external studies are separated from product statements

What pages on this site are not

Maintenance and updates

Related pages

Sources

Evidence status: educational synthesis, not a clinical outcome claim · Sources: see list below · Reviewer: pending veterinarian · Last updated: 2026-09-14