The Clinical Times
The Front Page of Medicine

Research Methods & Ethics · 1996

CONSORT Statement

Consolidated Standards of Reporting Trials

CONSORT-style flow diagram of a randomized controlled trial
PrevMedFellow / CC BY-SA 3.0 (Wikimedia Commons)

By the mid-1990s, systematic reviewers attempting to pool randomized trial data kept running into the same problem: trial reports omitted critical information. Whether allocation was concealed, how many patients withdrew and why, whether outcome assessors were blinded, what the original primary endpoint was before data collection began. These were not minor omissions; they were the variables that most powerfully predicted whether a trial's result was reliable. Meta-analyses built on incomplete reports could mislead as easily as they could inform.

A working group of methodologists convened to develop a minimum reporting standard for randomized trials. The result, published in JAMA in 1996, was the Consolidated Standards of Reporting Trials: a 21-item checklist covering every element necessary to judge an RCT's internal and external validity, accompanied by a patient-flow diagram that tracked enrollment, allocation, follow-up, and analysis. David Moher led the writing group; Douglas Altman, a biostatistician at Oxford, was central to the design of the statistical reporting requirements.

The checklist itself was not radical in what it asked for. These were items any methodologically literate reader would want to know. What was new was the mechanism: journals adopted CONSORT compliance as a submission requirement, making disclosure mandatory rather than aspirational. JAMA, The Lancet, and the BMJ were among the first adopters, and within a few years the list had grown to several hundred journals.

Audits of trial reporting quality before and after CONSORT adoption consistently showed improvement in the completeness of key elements, particularly allocation concealment and blinding descriptions. The 2001 revision clarified several ambiguous items. The 2010 revision expanded the checklist to 25 items and reorganized the flow diagram. CONSORT 2025 is the current version, with active extensions for cluster-randomized trials, noninferiority and equivalence trials, and structured abstracts.

CONSORT also catalyzed a broader reporting-standards movement. STROBE for observational studies, PRISMA for systematic reviews, STARD for diagnostic accuracy studies, and SPIRIT for trial protocols all followed the CONSORT model of a checklist plus explanatory document published in a high-impact journal and adopted by journals as a condition of submission. The 1996 paper is one of the most cited methodological publications in clinical research.

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Read the original — PubMed

JAMA, 1996

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