In 1993, 30 experts comprised of medical journal editors, clinical trialists, epidemiologists, and methodologists met in Ottawa, Canada with the aim of developing a new scale to assess the quality of randomized controlled trial (RCT) reports. However, during preliminary discussions, participants felt that many of the suggested scale items were irrelevant because they were not regularly reported by authors. In fact, there was accumulating evidence that the quality of reports of RCTs was less than optimal(322)(323). Therefore, unanimous agreement steered the remainder of the workshop to focus on ways to improve the reporting of RCTs.

Participants nominated items to be included in the checklist for which there was evidence, whenever possible, that not adequately reporting this information could lead to biased estimates of the benefits of the intervention under investigation. One outcome of the meeting was the Standardized Reporting of Trials (SORT) statement (315). This statement consisted of a 32-item checklist and flow diagram in which investigators were encouraged to report on the various aspects of how RCTs were conducted.

Concurrently, and independently, another group of experts, the Asilomar Working Group on Recommendations for Reporting of Clinical Trials in the Biomedical Literature, convened in Asilomar (California), USA, were working on a similar mandate. This group also published a proposal which included a checklist of recommended items for authors to consider when reporting RCTs(316).

At the suggestion of Drummond Rennie, Deputy Editor of JAMA, representatives from both groups met in 1996, in Chicago, USA. The remit of this group was to merge the best of the SORT and Asilomar proposals into a single, coherent evidence-based recommendation. It was felt that a single recommendation would have a better likelihood of appealing to journals and thus improve dissemination. The meeting resulted in the Consolidated Standards of Reporting Trials (CONSORT) Statement, which was first published in 1996(314).

Further meetings of the Group in 1999 and 2000 led to the publication of the revised CONSORT statement 2001. Following a meeting in January 2007, a further revision was developed and the CONSORT 2010 statement was published on March 24, 2010.

CONSORT Statement 2001

The CONSORT Statement is a continually evolving instrument, needing to be regularly updated in light of experience and new empirical evidence. Participants in the CONSORT Group and their degree of involvement vary over time. Key members meet regularly to review the need to further refine the CONSORT Statement.

At a meeting in May 1999, 13 participants of the CONSORT Group decided that there was a need to revise the original CONSORT checklist and flow diagram. The Group discussed the merits of including each item in light of current evidence, and determined, by consensus, the changes to be made in the revision.

As in developing the original CONSORT Statement, the intention was to keep only those items deemed fundamental to reporting standards for an RCT. Some items, which were not regarded as essential, could well be highly desirable and should still be included in a report of a randomized controlled trial even though they are not included in CONSORT. Such items included approval of an institutional ethics review board, sources of funding for the trial, and a trial registry number - e.g., the International Standard Randomized Controlled Trial Number (ISRCTN) used to register the RCT at its inception(324).

The revised CONSORT Statement was published in 2001, without precedent, simultaneously in three prestigious international medical journals(325)(326)(327).

Development of CONSORT 2010

Since the revision in 2001, the evidence base to inform CONSORT had grown considerably; empirical data had highlighted new concerns regarding the reporting of randomized controlled trials, such as selective outcome reporting.(55) (56) (57)

Therefore, a CONSORT Group meeting was convened. Thirty-one members of the CONSORT group met in Montebello, Canada in January 2007 to update the 2001 CONSORT Statement. In addition to the accumulating evidence relating to existing checklist items, several new issues had come to prominence since 2001. Some participants were given primary responsibility for aggregating and synthesizing the relevant evidence on a particular checklist item of interest. Based on that evidence, the group deliberated the value of each item. As in prior CONSORT versions, only those items deemed fundamental to reporting an RCT were kept. Moreover, an item may be fundamental to a trial but not included, such as approval by an institutional ethical review board, because funding bodies strictly enforce ethical review and medical journals usually address reporting ethical review in their instructions for authors. Other items may seem desirable, such as on-site monitoring, but a lack of empirical evidence or any consensus on their value cautions against inclusion at this point. The checklist thus addresses the minimum criteria.

After the meeting, the CONSORT Executive convened teleconferences and in-person meetings to revise the checklist.  After seven major iterations, a revised checklist was distributed to the larger group for feedback. With that feedback, the Executive met twice in person to consider all the comments and to produce a penultimate version. That served as the basis for writing the first draft of this paper, which was then distributed to the group for feedback.  After consideration of their comments, the Executive finalized the statement.

The CONSORT Executive then drafted an updated explanation and elaboration (E&E) manuscript, with assistance from other members of the larger group. The substance of the 2007 CONSORT meeting provided the material for the update. The updated E&E was distributed to the entire group for additions, deletions, and changes. That final iterative process converged to the CONSORT 2010 E&E.

On March 24, 2010, eight journals simultaneously published the CONSORT 2010 Statement, and two journals published the CONSORT 2010 E&E.

A summary of the specific changes to the CONSORT checklist was included in the CONSORT Statement.


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