Source hierarchy
We prefer sources that are directly responsible for clinical guidance, regulation, surveillance or peer-reviewed evidence. Depending on the topic, this can include international health authorities, national public-health agencies, medicines regulators, professional societies, evidence-based clinical guidelines, systematic reviews and peer-reviewed research.
Sources for conditions
For condition pages, priority is generally given to current clinical guidelines and authoritative public-health or specialty sources. Primary research is used when it adds information that is not adequately represented in current guidance or when the topic is evolving.
Sources for medicines
Drug pages should rely heavily on regulatory product information and authoritative medicines references for indications, contraindications, dosing constraints, interactions, pregnancy and lactation information, serious adverse effects and safety warnings. Examples may include regulator-approved labels or product information, official formularies, pharmacovigilance communications and clinical guidelines.
Recency
We prefer the most current appropriate source, but “newest” is not automatically “best”. A mature guideline may remain the strongest source until it is superseded. Publication and update dates are considered when the medical point is time-sensitive.
When sources disagree
Recommendations can differ between countries, societies and health systems. We do not silently collapse meaningful disagreements into a single universal rule. Where the difference matters, the article should describe the scope of the recommendation or identify which authority is being followed.
Statistics and geographic data
Prevalence, incidence, mortality and other population statistics are labelled with their geographic scope and source where possible. Global figures are not automatically presented as country-level estimates, and regional data should not be mixed with country data without explanation.
What we avoid
Commercial health websites, clinic marketing pages, anonymous summaries and search-engine snippets are not treated as primary evidence for medical claims. They may occasionally help locate an original source, which should then be checked directly.
Citations and links
Sources are listed so readers and reviewers can identify the basis for important claims. Links to legitimate regulators, employers, universities, professional organizations and evidence sources are editorial references, not endorsements.