The quality of a health article depends heavily on the quality of the evidence behind it. PlusGBUK therefore uses a source hierarchy rather than treating every link as equally reliable.
Sources we prefer
For UK medical and regulatory information we prioritise sources such as the NHS, NICE, MHRA, GOV.UK and relevant professional or statutory bodies.
For scientific questions we prefer peer-reviewed primary research, systematic reviews, high-quality clinical guidance and established research institutions. For international material, appropriate regulators and public-health bodies may include the US Food and Drug Administration, US Centers for Disease Control and Prevention, SAMHSA, European Medicines Agency and World Health Organization.
Primary evidence and interpretation
An individual study can be useful without being decisive. Study design, sample size, population, comparator, outcome and limitations affect what can reasonably be concluded. We avoid presenting an early laboratory finding, animal study or small observational study as proof of a clinical effect in people.
Secondary sources
High-quality secondary sources can be useful when they accurately summarise a large body of evidence. Commercial health sites, news stories and general reference pages may help identify a topic but should not replace a stronger primary or official source for an important medical or legal claim.
Links changing over time
External pages may move, be updated or disappear. A broken link does not automatically mean the underlying claim is wrong, but we aim to replace inaccessible references where a suitable authoritative source is available.
Source concerns can be sent to [email protected].