Term
Randomized controlled trial (RCT)
A trial that assigns participants to treatment or control by chance, so the groups differ only by the treatment.
Randomization is the strongest tool clinical research has: assigning patients to arms by chance balances both the differences you can measure and the ones you cannot, so an outcome difference can be attributed to the treatment rather than to who happened to receive it.
A controlled trial compares against something: placebo, an active comparator, or standard of care. Randomized plus controlled plus blinded is the design skeleton this site's top evidence grade requires, because it is the combination that historically survives confirmatory testing.
On this site: How design decides the grade ↗
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