CONSORT (Consolidated Standards of Reporting Trials) is the international reporting guideline for randomised controlled trials. It comprises a checklist of essential items and a participant flow diagram so that a trial report contains everything a reader needs to assess its conduct, validity and applicability — and so that another team could, in principle, reproduce the study.
What CONSORT is for
Randomised controlled trials sit near the top of the hierarchy of evidence because randomisation balances confounders. But that strength is only realisable if the trial is reported in full: an unreported deviation, a hidden change of primary outcome or an unexplained loss of participants can quietly undermine the randomisation. CONSORT exists to make the trial transparent. Like PRISMA, it is a reporting standard, not a method for designing or running a trial.
The checklist
The CONSORT checklist covers the trial report end to end — title and abstract, introduction, methods, results, discussion and other information. Its items target precisely the places where trials are most often under-reported:
| Section | Representative items |
|---|---|
| Methods | Trial design, eligibility, interventions, primary and secondary outcomes, sample-size calculation, randomisation sequence generation, allocation concealment, blinding |
| Results | Participant flow diagram, recruitment dates, baseline data, numbers analysed, outcomes and estimation with effect size and precision, harms |
| Other | Registration, protocol availability, funding |
Several items deserve emphasis. Reporting how the random sequence was generated, how allocation was concealed and who was blinded lets readers judge whether the randomisation was protected from subversion. Pre-specifying the primary outcome and reporting it — alongside trial registration — guards against outcome-switching. Stating the sample-size calculation shows whether the trial was adequately powered.
The flow diagram
CONSORT’s flow diagram tracks participants through four stages — enrolment, allocation, follow-up and analysis. It records how many were assessed for eligibility, how many were randomised to each arm, how many received the intended intervention, how many were lost to follow-up and how many were included in the analysis. Because attrition and exclusions can bias results, a complete diagram is one of the most informative parts of any trial report.
CONSORT in the EQUATOR family
CONSORT is one of the foundational guidelines maintained through the EQUATOR Network, the same initiative that curates PRISMA for systematic reviews and STROBE for observational studies. The EQUATOR philosophy is design-matched reporting: use CONSORT for randomised trials, STROBE for cohort and case-control studies, PRISMA for reviews. CONSORT also has a family of extensions for specific trial types — cluster trials, pilot and feasibility trials, non-inferiority designs, abstracts and harms reporting — so authors should select the relevant extension alongside the core checklist.
Why complete reporting matters
Incomplete trial reporting is not a cosmetic problem. It wastes research investment, frustrates the systematic reviews that depend on extractable data, and can mislead decisions. CONSORT-adherent reporting feeds directly into the meta-analyses that synthesise trials, which is why journals across many fields endorse it. For the wider context, see our overview of reporting guidelines and EQUATOR, the CASRAI dictionary and our reproducibility coverage.
Frequently asked questions
Is CONSORT mandatory?
CONSORT is endorsed by a large number of journals and editorial bodies, which often require adherence as a condition of submission. It is a community standard rather than a law, but for randomised trials it is the expected reporting framework.
How does CONSORT differ from PRISMA?
CONSORT governs the reporting of an individual randomised controlled trial; PRISMA governs the reporting of a systematic review or meta-analysis that may synthesise many trials. Both are EQUATOR guidelines but apply at different stages of the evidence pipeline.
Does CONSORT cover trial registration?
Yes. CONSORT asks authors to report the trial registration number and where the full protocol can be accessed, which lets reviewers check the reported outcomes against the pre-specified ones.
Which CONSORT extension should I use?
Select the extension that matches your design — for example the cluster-trial or pilot-and-feasibility extension — in addition to the core checklist. The EQUATOR library lists the current extensions; our author guidance points to them.
