{"entity":{"id":"randomised-trial","kind":"term","name":"Randomised trial","aka":["randomised","randomized","randomisation","randomization","randomly assigned","randomised controlled trial","randomized controlled trial","RCT","RCTs","randomised trials","randomized trials","randomised phase 3","randomized phase 3","controlled trial","head-to-head","controlled trials","randomized trial"],"tldr":"A trial in which a coin toss (done by computer) decides which treatment each patient gets, so the groups are alike in every way except the treatment. It is the only reliable way to prove a treatment causes a benefit.","summary":"Without randomisation, patients who receive a new drug tend to differ from those who do not (fitter, younger, treated at better centres), and those differences, not the drug, may explain a better outcome; randomising removes this bias, and analysing every patient in the group they were assigned to (intention-to-treat) preserves it. The control group receives the current standard of care, sometimes with a placebo added so that the two arms look identical, and the trial is powered so that a real difference of a given size is unlikely to be missed. Large randomised trials are slow and expensive, which is why surrogate endpoints, single-arm accelerated approvals and real-world evidence are all attempts to shortcut them, each with known pitfalls.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Randomized_controlled_trial","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Randomized_controlled_trial"},{"label":"CONSORT statement: reporting randomised trials","url":"https://www.consort-statement.org/"}],"tags":[],"related":["clinical-trial","placebo","blinding","trial-phases","hazard-ratio","p-value","confidence-interval","standard-of-care","real-world-evidence","stratified-randomisation","clinical-equipoise","cluster-randomised-trial","pragmatic-trial","intention-to-treat","kaplan-meier-curve","non-inferiority","trial-failure-modes","estimand"],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":["checkmate-067","adaura","interlace","challenge","protect"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Clinic basics"},"route":"/terms/randomised-trial/","neighbours":{"term":[{"id":"blinding","kind":"term","name":"Blinded trial","route":"/terms/blinding/"},{"id":"clinical-equipoise","kind":"term","name":"Clinical equipoise","route":"/terms/clinical-equipoise/"},{"id":"clinical-trial","kind":"term","name":"Clinical trial","route":"/terms/clinical-trial/"},{"id":"cluster-randomised-trial","kind":"term","name":"Cluster-randomised trial","route":"/terms/cluster-randomised-trial/"},{"id":"confidence-interval","kind":"term","name":"Confidence interval","route":"/terms/confidence-interval/"},{"id":"endpoint","kind":"term","name":"Endpoint","route":"/terms/endpoint/"},{"id":"estimand","kind":"term","name":"Estimands and intercurrent events (ICH E9(R1))","route":"/terms/estimand/"},{"id":"hazard-ratio","kind":"term","name":"Hazard ratio (HR)","route":"/terms/hazard-ratio/"},{"id":"intention-to-treat","kind":"term","name":"Intention-to-treat (ITT) and per-protocol analysis","route":"/terms/intention-to-treat/"},{"id":"kaplan-meier-curve","kind":"term","name":"Kaplan-Meier curve, censoring and proportional hazards","route":"/terms/kaplan-meier-curve/"},{"id":"n-of-1-trial","kind":"term","name":"N-of-1 trial","route":"/terms/n-of-1-trial/"},{"id":"non-inferiority-margin","kind":"term","name":"Non-inferiority margin and equivalence trials","route":"/terms/non-inferiority-margin/"},{"id":"non-inferiority","kind":"term","name":"Non-inferiority trial","route":"/terms/non-inferiority/"},{"id":"p-value","kind":"term","name":"P-value","route":"/terms/p-value/"},{"id":"trial-phases","kind":"term","name":"Phase 1, 2 and 3 trials","route":"/terms/trial-phases/"},{"id":"placebo","kind":"term","name":"Placebo","route":"/terms/placebo/"},{"id":"pragmatic-trial","kind":"term","name":"Pragmatic trial","route":"/terms/pragmatic-trial/"},{"id":"real-world-evidence","kind":"term","name":"Real-world evidence","route":"/terms/real-world-evidence/"},{"id":"registry-based-trial","kind":"term","name":"Registry-based randomised trial","route":"/terms/registry-based-trial/"},{"id":"smart-design","kind":"term","name":"SMART design (sequential multiple assignment randomised trial)","route":"/terms/smart-design/"},{"id":"standard-of-care","kind":"term","name":"Standard of care","route":"/terms/standard-of-care/"},{"id":"stepped-wedge-design","kind":"term","name":"Stepped-wedge design","route":"/terms/stepped-wedge-design/"},{"id":"stratified-randomisation","kind":"term","name":"Stratified randomisation, allocation concealment and minimisation","route":"/terms/stratified-randomisation/"},{"id":"trial-failure-modes","kind":"term","name":"Why trials fail: underpowered, wrong endpoint, control arm drift, subgroup fishing, crossover","route":"/terms/trial-failure-modes/"}],"trial":[{"id":"adaura","kind":"trial","name":"ADAURA","route":"/trials/adaura/"},{"id":"challenge","kind":"trial","name":"CHALLENGE (CCTG CO.21)","route":"/trials/challenge/"},{"id":"checkmate-067","kind":"trial","name":"CheckMate 067","route":"/trials/checkmate-067/"},{"id":"interlace","kind":"trial","name":"INTERLACE","route":"/trials/interlace/"},{"id":"protect","kind":"trial","name":"ProtecT","route":"/trials/protect/"}],"idea":[{"id":"idea-moon-question-prompt-lists","kind":"idea","name":"Question prompt lists sent to patients before every major consultation","route":"/ideas/idea-moon-question-prompt-lists/"}],"journal":[{"id":"international-journal-of-clinical-oncology","kind":"journal","name":"International journal of clinical oncology","route":"/journals/international-journal-of-clinical-oncology/"},{"id":"lancet-haematology","kind":"journal","name":"The Lancet Haematology","route":"/journals/lancet-haematology/"}]}}