Introduction

“Readers should not have to infer what was probably done; they should be told explicitly.” Douglas G Altman [1]

Randomised trials, when appropriately designed, conducted, analysed, and reported, are generally considered the highest quality evidence in evaluating healthcare interventions. Critical appraisal of the quality of randomised trials is possible only if their design, conduct, analysis, and results are thoroughly and accurately reported. To interpret a trial accurately, readers need complete and transparent information on its methods and findings. However, extensive evidence displays that the completeness of reporting of randomised trials is inadequate [2,3] and that incomplete reporting may be associated with biased estimates of intervention effects [4]. Similarly, having a clear and transparent trial protocol is important because it prespecifies the methods used in the trial, such as the primary outcome, thereby reducing the likelihood of undeclared post hoc changes [5].

Efforts to improve the reporting of randomised trials gathered impetus in the early 1990s and resulted in the Standardised Reporting of Trials (SORT) and Asilomar initiatives in 1994. Those initiatives then led to publication of the CONSORT (Consolidated Standards of Reporting Trials) statement in 1996 [6], revised in 2001 [7] with an accompanying explanation and elaboration document [8]. CONSORT was then updated in 2010 [9], along with an updated explanation and elaboration article [10]. Similar problems related to the lack of complete and transparent reporting of trial protocols led to the development of the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) statement, published in 2013 [11], and its accompanying explanation and elaboration document [12] explaining the principles underlying the statement.

CONSORT is endorsed by numerous journals worldwide and by prominent editorial organisations, including the World Association of Medical Editors (WAME), International Committee of Medical Journal Editors (ICMJE) and Council of Science Editors (CSE). The introduction of CONSORT within journals has been shown to be associated with improved quality of reports of randomised trials. Some evidence shows that journal endorsement of CONSORT is associated with better reporting and that reporting is improving over time [2,13–15]. A Cochrane review of 50 evaluations of 16,604 trials assessed the association between journals’ endorsement of CONSORT and the reporting of trials they published; 25 of 27 CONSORT checklist items were more completely reported when a trial was published in a CONSORT endorsing as opposed to non-endorsing journal [2,14]. However, a causal effect cannot be proven. At a minimum, CONSORT has sensitised many end users (e.g., authors, journal editors, and peer reviewers) to how important careful and thorough reporting can be for randomised trials.

SPIRIT and CONSORT are evidence-based guidelines that comprise a checklist of essential items that should be included in protocols and primary reports of completed randomised trials, respectively, and a diagram that documents the flow of participants through a trial. These statements provide guidance to authors on the minimum information that should be included in the reporting of trials to ensure that trial protocols and trial reports are clear and transparent. They are published alongside explanation and elaboration documents, which provide the meaning and rationale for each checklist item, examples of good reporting, and relevant empirical evidence where possible.

In January 2020, the SPIRIT and CONSORT executive groups met in Oxford, UK. As the SPIRIT and CONSORT statements are conceptually linked, with overlapping content and similar dissemination and implementation strategies, the two groups decided it was more effective to work together and formed one group. The CONSORT 2025 statement is being simultaneously published in The BMJ, JAMA, The Lancet, Nature Medicine, and PLOS Medicine.

Decision to update the SPIRIT and CONSORT statements

SPIRIT and CONSORT are living guidelines and it is vital that the statements are periodically updated to reflect new evidence, methodological advancements, and feedback from users; otherwise, their value and usefulness will diminish over time[16]. Updating the SPIRIT 2013 and CONSORT 2010 statements together was also an opportunity to further align both checklists and to provide users with consistent guidance in the reporting of trial design, conduct, analysis, and results from trial protocol to final publication. Harmonising the reporting process should improve usability and adherence, and lead to more-complete reporting [17]. Here, we introduce the updated CONSORT 2025 statement; the updated SPIRIT 2025 statement is published separately [18].

Development of CONSORT 2025

The methods used to update the CONSORT statement followed the EQUATOR Network guidance for developers of health research guidelines [19] and have been described in detail elsewhere [20,21]. In brief, we first conducted a scoping review of the literature to identify published comments suggesting modifications and additions or reflecting on strengths and challenges of CONSORT 2010, the findings of which have been published separately [22]. We also developed a project specific database (SCEBdb) for empirical and theoretical evidence related to CONSORT and risk of bias in randomised trials [23]. The evidence identified in the scoping review was combined with evidence from, and recommendations provided by the lead authors of, certain key existing CONSORT extensions whose checklist items apply to all trials (Harms [24], Outcomes [25]), or a considerable number of trials [26] (Non-pharmacological Treatment [27]), other related reporting guidelines (the template for intervention description and replication (TIDieR) [28]), and recommendations from other sources (e.g., personal communications).

Using the existing CONSORT 2010 checklist as the starting point, a list of potential modifications or additions to the checklists was then created using the gathered evidence from the scoping review and recommendations. This list of potential changes was presented to end users for feedback in a large international online Delphi survey, involving 317 participants who responded to round 1, 303 to round 2 and 290 to round 3. Delphi participants were identified through existing SPIRIT and CONSORT collaborations, and professional research networks and societies. Participants were also recruited via an expression of interest form on the SPIRIT-CONSORT update project website. A broad range of end user roles were represented, the most frequent being statisticians/methodologists/epidemiologists (n = 198), systematic reviewers/guideline developers (n = 73), trial investigators (n = 73), clinicians (n = 58), journal editors (n = 47), and patient representatives (n = 17) (numbers not mutually exclusive). During the three-round Delphi survey, participants were asked to rate on a 5-point Likert scale the extent to which they agreed with the inclusion of each item in the updated CONSORT checklist. Free text boxes were provided for comments on each item and to suggest additional new checklist items.

The Delphi survey results were then presented and discussed at a two-day online expert consensus meeting via Zoom, on 1 and 2 March 2023, attended by 30 invited international participants representing the different stakeholder groups included in the Delphi survey. During the meeting, each new and modified CONSORT checklist item was discussed and agreement sought. An anonymous poll via Zoom was used to help establish the level of support for items where the discussion indicated differing opinions; these polls were advisory and no formal consensus threshold was specified.

After the expert consensus meeting, the executive group held a two-day, in-person writing meeting in Oxford on 25 and 26 April 2023, where the format and wording of each new or modified CONSORT checklist item was reviewed and agreed on. The draft checklist was then circulated to consensus meeting participants to confirm whether they represented the group consensus or needed clarification. CONSORT items were further revised by the executive group in response to this feedback. The finalised items address the minimum content for inclusion in a trial report, although that should not deter prospective authors from including additional information that they deem important or that facilitates replication. Members of the executive group and the 30 invited consensus meeting participants are authors of the manuscript and their names are listed at the end of the manuscript.

Main changes to CONSORT 2025

We have made a number of substantive changes to the CONSORT 2025 checklist (see Box 1). We have added seven new checklist items, revised three items, deleted one item, and integrated several items from key CONSORT extensions (Harms [24], Outcomes [25], Non-pharmacological Treatment [27]) and other related reporting guidelines (TIDieR [28]). We also restructured the CONSORT checklist, with a new section on open science, which includes items that are conceptually linked, such as trial registration (item 2), where the trial protocol and statistical analysis plan can be accessed (item 3), sharing of de-identified participant level data (item 4), and funding and conflicts of interest (item 5). We have also harmonised the wording between CONSORT and SPIRIT checklist items and clarified and simplified the wording of some items. For a detailed comparison of the changes made in the CONSORT 2025 checklist from CONSORT 2010, see S1 Appendix. We have also updated the CONSORT explanation and elaboration document [29], which has been extensively revised and describes the rationale and scientific background for each CONSORT 2025 checklist item and provides published examples of good reporting.

To help facilitate implementation of CONSORT 2025, we have also developed an expanded version of the CONSORT 2025 checklist, with bullet points eliciting critical elements of each item. This is similar to the model proposed by the COBWEB (CONSORT-based web tool) [30] and COBPeer (CONSORT based peer review tool) [31] studies and used in the 2020 PRISMA guidance for reporting systematic reviews [32]. The expanded checklist comprises an abridged version of elements presented in the CONSORT 2025 explanation and elaboration document [29], with examples and references removed (see S2 Appendix).

Scope of CONSORT 2025

The CONSORT 2025 statement comprises a 30-item checklist and provides a minimum set of items to be included in a report of a randomised trial (Table 1) and a diagram for documenting the flow of participants through a trial (Fig 1). We strongly recommend the CONSORT 2025 statement be used alongside the CONSORT 2025 explanation and elaboration document [29]. The CONSORT 2025 statement supersedes the CONSORT 2010 statement, which should no longer be used. Journal editors and publishers should update their instructions to authors to refer to CONSORT 2025. CONSORT 2025 provides guidance for reporting all randomised trials but focuses on the most common type, the two-group parallel design.

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Table 1. CONSORT 2025 checklist of information to include when reporting a randomised trial.

https://doi.org/10.1371/journal.pmed.1004587.t001

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Fig 1. CONSORT 2025 flow diagram.

Flow diagram of the progress through the phases of a randomised trial of two groups (i.e., enrolment, intervention allocation, follow-up, and data analysis). CONSORT = Consolidated Standards of Reporting Trials.

https://doi.org/10.1371/journal.pmed.1004587.g001

Extensions to CONSORT have been developed to tackle the methodological issues associated with reporting different types of trial designs, data, and interventions. Examples of extensions for trial designs include recommendations for adaptive designs [33], cluster trials [34], crossover trials [35], early phase trials [36], factorial trials [37], non-inferiority and equivalence trials [38], pragmatic trials [39], multi-arm trials [40], n-of-1 trials [41], pilot and feasibility trials [42], and within-person trials [43]. Other extensions include non-pharmacological treatments [27], outcomes [25], patient reported outcomes [44], surrogate outcomes [45], social and psychological interventions [46], harms [24], abstracts [47], and health equity [48]. We will engage with the leaders of these extensions to implement a process for aligning them with the updated CONSORT 2025 statement. In the meantime, we recommend that readers use the existing version of the relevant CONSORT extension(s).

Implication and limitations

The objective of the CONSORT 2025 statement is to provide a minimum set of recommendations to authors about the content they should include in order to report their trials in a clear, complete, and transparent manner [9,10]. Readers, peer reviewers, clinicians, guideline writers, patients and the public, and editors can also use CONSORT 2025 to help them appraise the reporting of randomised trials. We also strongly recommend the submission of a completed CONSORT 2025 checklist as part of the manuscript submission process, detailing where in the manuscript checklist items are reported, and uploaded as part of the supplementary materials [49]. An explicit description of what was done and what was found, without ambiguity or omission, best serves the interests of all readers [9].

It is important to note that CONSORT 2025 and SPIRIT 2025 do not include recommendations for designing, conducting, or analysing trials, but nevertheless the recommendations contained here can help researchers in the design, conduct, and analysis of their trial by highlighting key issues to consider. Updating the SPIRIT and CONSORT statements together was also an opportunity to align reporting in both checklists and to provide users with consistent guidance in the reporting of trial design, conduct, and analysis, from the trial protocol to final publication [17]. Thus, clear and transparent reports of trial protocols should in turn facilitate properly designed and well conducted trials. In addition, transparent reporting of trial results can reveal deficiencies in research if they exist and allow better estimates of their prevalence and severity. Importantly, however, CONSORT 2025 is not meant to be used as a quality assessment instrument. Rather, the content of CONSORT 2025 focuses on reporting items related to the internal and external validity of randomised trials.

With CONSORT 2025, we do not suggest a rigid structure for the reporting of randomised trials. Instead, the format of articles should abide by the journal’s individual style and its “Instructions to Authors.” Authors should address checklist items somewhere in the article, with sufficient detail and clarity [9]. We also promote the use of additional online supplementary material to allow for more detailed reporting of the trial methods and results than may be permissible within the typical length of some print journal articles. Full data and code sharing offers another, higher level of transparency and we recommend providing detailed information on whether this is happening or planned to happen (e.g., after some time) in a randomised trial.

CONSORT urges clarity and transparency of reporting which reflects the actual trial design, conduct, and analysis. High quality reporting is an important step when considering issues related to reproducibility [50]. We encourage trial authors to detail what was done and to acknowledge if something was not done or was modified, ensuring alignment of information with that reported in the trial protocol, statistical analysis plan, and trial registry. A joint SPIRIT-CONSORT website (https://www.consort-spirit.org/) has been established to provide more information about the CONSORT and SPIRIT statements, including additional resources and training materials aimed at researchers, research trainees, journal editors, and peer reviewers. The website also includes resources aimed at patients and the public that explain the importance of clear and transparent reporting of randomised trials and their importance in the delivery of evidence based healthcare.

CONSORT 2025 represents a living guideline that will continue to be periodically updated to reflect new evidence and emerging perspectives. Such an approach is important to ensure the guidance remains relevant to end users, including authors, patients and the public, journal editors, and peer reviewers.

Supporting information

Acknowledgments

SPIRIT-CONSORT executive group: Sally Hopewell, University of Oxford, UK; An-Wen Chan^, University of Toronto, Canada; Asbjørn Hróbjartsson, University of Southern Denmark, Odense, Denmark; David Moher, University of Ottawa, Canada; Kenneth Schulz, University of North Carolina at Chapel Hill, USA; Isabelle Boutron, Université Paris Cité, France. Gary Collins and Ruth Tunn, both of University of Oxford, UK, were also involved in leading the SPIRIT and CONSORT 2025 update.

SPIRIT-CONSORT 2025 consensus meeting participants: Rakesh Aggarwal, Jawaharlal Institute of Postgraduate Medical Education and Research, India; Michael Berkwits, Office of the Centers for Disease Control and Prevention, USA (formally JAMA and the JAMA Network at time of consensus meeting); Jesse A Berlin, Rutgers University/JAMA Network Open USA; Nita Bhandari, Society for Applied Studies, India; Nancy J Butcher, The Hospital for Sick Children, Canada; Marion K Campbell, University of Aberdeen, UK; Runcie CW Chidebe, Project PINK BLUE, Nigeria/Miami University, Ohio, USA; Diana Elbourne, London School of Hygiene and Tropical Medicine, UK; Andrew J Farmer, University of Oxford, UK; Dean A Fergusson, Ottawa Hospital Research Institute, Canada; Robert M Golub, Northwestern University, USA; Steven N Goodman, Stanford University, USA; Tammy C Hoffmann, Bond University, Australia; John PA Ioannidis, Stanford University, USA; Brennan C Kahan, University College London, UK; Rachel L Knowles, University College London, UK; Sarah E Lamb, University of Exeter, UK; Steff Lewis, University of Edinburgh, UK; Elizabeth Loder, The BMJ, UK; Martin Offringa, Hospital for Sick Children Research Institute, Canada; Dawn P Richards, Clinical Trials Ontario, Canada; Frank W Rockhold, Duke University, USA; David L Schriger, University of California, USA; Nandi L Siegfried, South African Medical Research Council, South Africa; Sophie Staniszewska, University of Warwick, UK; Rod S Taylor, University of Glasgow, UK; Lehana Thabane, McMaster University/St Joseph’s Healthcare, Canada; David Torgerson, University of York, UK; Sunita Vohra, University of Alberta, Canada; and Ian R White, University College London, UK.

We dedicate CONSORT 2025 to the late Doug Altman who was instrumental in the development of the SPIRIT and CONSORT statements and whose files and correspondence contributed to this update following his death. We gratefully acknowledge the contributions of all those who participated in the SPIRIT-CONSORT 2025 update Delphi survey. We also acknowledge Camilla Hansen Nejstgaard for conducting the scoping review of the literature to identify suggested changes to CONSORT 2010 and for comparing CONSORT 2025 with RoB2, Lasse Østengaard for developing the SCEB (SPIRIT-CONSORT Evidence Bibliographic) database of empirical evidence to support the development of CONSORT, Jen de Bayer and Patricia Logullo for their involvement during the consensus meeting, and Lina El Ghosn for initial drafting of the expanded CONSORT checklist.

Ethical approval: Ethical approval was granted by the Central University Research Ethics Committee, University of Oxford (R76421/RE001). All Delphi participants provided informed consent to participate.

Patient and public involvement: The CONSORT 2025 checklist items and the explanations here were developed using input from an international Delphi survey and consensus meeting. The Delphi survey was advertised via established patient and public involvement (PPI) networks, and 17 respondents self-identified as a “patient or public representative” and completed the Delphi survey. In addition, three of the participants in the expert consensus meeting were patient or public representatives who were leaders in advancing PPI.

Dissemination to participants and related patient and public communities: CONSORT 2025 will be disseminated via a new website, consort-spirit.org, which will include materials designed for patients and the public.