The CONSORT (CONsolidated Standards of Reporting Trials) 2010 guideline is intended to improve the reporting of parallel-group randomized controlled trial (RCT), enabling readers to understand a trial's design, conduct, analysis and interpretation, and to assess the validity of its results. This can only be achieved through complete adherence and transparency by authors.
CONSORT 2010 was developed through collaboration and consensus between clinical trial methodologists, guideline developers, knowledge translation specialists, and journal editors (see CONSORT group ). CONSORT 2010 is the current version of the guideline and supersedes the 2001 and 1996 versions . It contains a 25-item checklist and flow diagram, freely available for viewing and downloading through this website.
Extensions of the CONSORT Statement have been developed for different types of trial designs, different interventions, and different types of data.
The most important documents for understanding the CONSORT 2010 statement are the following:
The CONSORT 2010 Statement: This is a declaration of the standard, and how it was developed. This declaration or "statement" has been published in many prominent journals, including the British Medical Journal, the Lancet and PLoS Medicine. You can download the CONSORT 2010 Statement documents here.
The CONSORT 2010 Explanation and Elaboration (E&E) Document: This 32-page document provides an explanation of each of the CONSORT Checklist items, and how to apply them in your reporting. You can download the CONSORT 2010 E&E Document here.
The CONSORT 2010 Checklist: This is a checklist of each of the 25 items that must be reported in a Randomized Clinical Trial Report in order for it to be compliant with the standard. You can see an example of how the CONSORT checklist can be applied to a well-reported study by navigating to the Sample Study in the menu above. You can download the CONSORT 2010 Checklist here.
The CONSORT 2010 Flow Diagram: This is a simple flow diagram showing how your study population was recruited and handled during the course of your study. You must complete a flow diagram in order to be compliant with the CONSORT 2010 standard. You can download the CONSORT 2010 Flow Diagram template here.
The CONSORT Statement and the CONSORT Explanation and Elaboration Document are distributed under the terms of the Creative Commons Attribution CC BY 2.0, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited.
Because the CONSORT guidelines were developed using a consensus process and agreed through successive drafts by the CONSORT Group, they should not be edited or modified in any way, although it is acceptable to publish portions (e.g., the summary, checkilst), with proper attribution
When referring to the CONSORT guideline, please cite one of the original CONSORT 2010 Statement articles and/or the CONSORT 2010 Explanation and Elaboration (E&E):
CONSORT 2010 Statement:
CONSORT 2010 E&E:
The checklist includes the 25 items selected because empirical evidence indicates that not reporting the information is associated with biased estimates of treatment effect, or because the information is essential to judge the reliability or relevance of the findings.
The checklist items pertain to the content of the Title, Abstract, Introduction, Methods, Results, Discussion, and Other information. You can explore the details of these items, as found in the CONSORT 2010 Explanation and Elaboration document, by clicking on the relevant checklist item titles below. These links will open a dynamic application we have created that allows you to explore and interact with the CONSORT checklist and all of its extensions.
1a Title– Identification as a randomised trial in the title.
1b Abstract – Structured summary of trial design, methods, results, and conclusions
2a Background – Scientific background and explanation of rationale
2b Objectives – Specific objectives or hypothesis
3a Trial design – Description of trial design (such as parallel, factorial) including allocation ratio
3b Changes to trial design – Important changes to methods after trial commencement (such as eligibility criteria), with reasons
4a Participants – Eligibility criteria for participants
4b Study settings – Settings and locations where the data were collected
5 Interventions – The interventions for each group with sufficient details to allow replication, including how and when they were actually administered
6a Outcomes – Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed
6b Changes to outcomes – Any changes to trial outcomes after the trial commenced, with reasons
7a Sample size – How sample size was determined
7b Interim analyses and stopping guidelines – When applicable, explanation of any interim analyses and stopping guidelines
8a Randomisation: sequence generation – Method used to generate the random allocation sequence
8b Randomisation: type – Type of randomisation; details of any restriction (such as blocking and block size)
9 Randomisation: allocation concealment mechanism – Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned)
10 Randomisation: implementation – Who generated the allocation sequence, who enrolled participants, and who assigned participants to interventions
11a Blinding – If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how
11b Similarity of interventions – If relevant, description of the similarity of interventions
12a Statistical methods – Statistical methods used to compare groups for primary and secondary outcomes
12b Additional analyses – Methods for additional analyses, such as subgroup analyses and adjusted analyses
13a Participant flow – For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome
13b Losses and exclusions – For each group, losses and exclusions after randomisation, together with reasons
14a Recruitment – Dates defining the periods of recruitment and follow-up
14b Reason for stopped trial – Why the trial ended or was stopped
15 Baseline data – A table showing baseline demographic and clinical characteristics for each group
16 Numbers analysed – For each group, number of participants (denominator) included in each analysis and whether the analysis was by original assigned groups
17a Outcome and estimation – For each primary and secondary outcome, results in each group, and the estimated effect size and its precision (such as 95% confidence interval)
17b Binary outcomes – For binary outcomes, presentation of both absolute and relative effect sizes is recommended
18 Ancillary analyses – Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-specified from exploratory
19 Harms – All important harms or unintended effects in each group
20 Limitations – Trial limitations, addressing sources of potential bias, imprecision, and, if relevant, multiplicity of analyses
21 Generalisability – Generalisability (external validity, applicability) of the trial findings
22 Interpretation – Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence
23 Registration – Registration number and name of trial registry
24 Protocol – Where the full trial protocol can be accessed, if available
25 Funding – Sources of funding and other support (such as supply of drugs), role of funders
One feature of the original CONSORT Statement in 1996(314), shared by its two precursors (315)(316), was the near absence of any explanation of the concepts or justification for the importance of specific information being needed in reports of randomized trials. It was recommended that the value of the CONSORT Statement, and probably also its acceptability, could be enhanced by the development of a second publication that clarified the scientific background and explained why each issue was important(317).
Therefore when the CONSORT Statement was revised in 1999, the opportunity was taken to develop, in parallel to the revised checklist, a detailed explanatory document. The resulting 32-page Expanation and Elaboration (E&E) document was published simultaneously with the revised CONSORT Statement in the Annals of Internal Medicine in 2001(318)(319). It was recognized as an important innovation and the idea has subsequently been taken up by other reporting guideline groups(320)(321).
The E&E document addresses each checklist item individually. For each item, key methodological issues are explained and a summary of the empirical evidence about the importance of reporting that item is provided. Examples of clear reporting are also given for each checklist item.
It is recommended that the CONSORT Statement checklist is read in conjunction with the accompanying E&E document. As such, whenever the CONSORT checklist is updated, the accompanying E&E document will also be updated. You can download the CONSORT 2010 E&E Document here.