How we evaluate research
Every item we cover is graded so you can see how much weight it deserves.
Evidence grade (study type)
- A — systematic review / meta-analysis
- B — randomized controlled human trial
- C — observational human study
- D — animal study
- E — cell / lab / in vitro
- F — commentary / hypothesis / news-only
Grade describes the type of study, not its quality. We separately
flag sample size, industry funding, preregistration, and whether a result is a
preprint (not yet peer reviewed).
Retractions
We check studies against retraction records. A retracted study is never
presented as standing evidence; we may only cover it as a retraction.
Risk level
Mental-health and other sensitive topics get a stronger disclaimer, crisis
resources, and human review before publishing.
News is a discovery signal; the original paper is the evidence.