Glossary · Methodology
Randomized controlled trial (RCT)
In short
In a randomized controlled trial, chance decides who receives the treatment and who goes into the comparison group. Because the groups then differ on average only in the treatment, it can separate cause and effect.
That is the difference from observation: people who take a supplement voluntarily often live more healthily in other ways too. Drawing lots spreads such differences — known and unknown — evenly across both groups.
The comparison group usually receives a placebo, sometimes the usual standard treatment. If neither participants nor study team know who gets what, the trial is called double-blind.
An RCT is not automatically good. If it is small, short, measures only a lab value or loses many participants, it carries little weight. In the BK-Score, human evidence therefore only reaches the top range when large randomized trials measure hard endpoints.
Chance also distributes what nobody can measure.
Where this comes up in the fact checks
- Aspirin for prevention – In the ASPREE trial, 19,114 older people were randomly assigned to aspirin or placebo; no benefit emerged, but there were more major bleeds.
- CGM (blood glucose sensor) – For people without diabetes, our research found no randomized trial demonstrating a health benefit.
- BPC-157 – Three small human studies with 30 people, none of them randomized.
Sources
Related terms: Placebo · Double-blind · Observational study · Meta-analysis
Information only, not medical advice. The BK-Score is a subjective assessment according to disclosed rules – not a scientific evaluation. Scoring rules