Evidence Tier
human_rct
Last updated
Rung 1, the top of this site's seven-rung evidence ladder. A claim earns it when at least one prospective trial in human participants, with randomised allocation and a control arm, reports the specific outcome that claim is about. Allocation must have been randomised before the outcome was measured, participant number and effect size must be reported with a measure of uncertainty, and trial registration is either recorded or its absence stated. The full criteria, including what disqualifies, are published at /evidence/rubric.
Flagged for specialist review
This entry describes something contested, or asserts a detail we have not been able to confirm against a settled source. It is published rather than withheld, with the flag visible, because an entry you can weigh beats a gap you cannot see.
Why it matters here
It is the only rung on which a claim may be worded causally, so the shift in language between a rung 1 line and a rung 2 line on the same record is deliberate rather than stylistic.
What it is not
A rung 1 grade belongs to one claim, never to the compound: a trial establishing glycaemic control does not grade a claim about hair growth or muscle retention for the same molecule, and that is the most common misreading in this category. A single-arm study is not an RCT however the paper describes itself, and a conference abstract is capped one rung lower until full methods are published.
Also called
- rct
- randomized controlled trial
- human rct
- clinical trial
- phase 3
- phase iii
Clinical trial, phase 3 and phase III are looser than this rung: grading follows the design, so a randomised early-phase trial qualifies while a large single-arm study called a clinical trial does not.
Compounds carrying this term
None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.