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Study protocol


Study protocol articles will generally only be considered for proposed or ongoing trials that have not completed participant recruitment at the time of submission. Trials advises that study protocols are submitted well before recruitment completes, however, we will also, on occasion, consider study protocols submitted well before the last patient/last visit. In such cases, the expected last patient/last visit date and an explanation of why it was not possible to submit earlier, should be included within the manuscript text. Please confirm the status of your study at submission.

Trials also considers study protocols assessing aspects of the design, conduct or reporting of randomized trials. These studies do not necessarily need to be trials and include studies such as core outcome set development for use in trials and process evaluations that run alongside trials. Please follow the relevant reporting guideline for the study design and include the corresponding checklist as an additional file.

All submitted protocols must have ethical approval.  If the study has undergone full external peer review as part of the funding process, the study protocol will usually only undergo editorial peer review by a Protocol Editor. Study protocols without major external funding will undergo full, external peer review. Study protocols without ethical approval will generally not be considered. To support efficient handling of your study protocol, the Editors advise that prospective authors familiarize themselves with this Editorial on what is expected in a study protocol submission.

Trials welcomes public and patient co-authors. Where a study explicitly mentions patient or public involvement in the design, delivery or dissemination of the study, we would anticipate that there would be at least one patient or public co-author.

Please note: From 1st January 2021, Trials will no longer consider study protocols for pilot or feasibility trials for publication. We recommend that these manuscripts are instead submitted to our sister journal, Pilot and Feasibility Studies.

Statistical Analysis Plans can be directly integrated into the study protocol being submitted for publication (for uncomplicated RCTs this might be sufficient) or included as an additional file to the submission. For more information, read our Editorial: Prospective reporting of statistical analysis plans for randomised controlled trials. Standalone statistical analysis plans submitted separately to a study protocol should be submitted as an Update. These should be submitted before data lock.

Additional Files

On submission, the following documentation should be uploaded as Additional Files. If the original documents are not in English, an English translation of each is mandatory.

  • Ethical approval document
  • Copy of the original funding documentation
  • A completed SPIRIT checklist (unless the structured study protocol template has been used), or checklist for another appropriate reporting guideline

SPIRIT Guidance

Study protocols reporting a clinical trial can be formatted for submission to Trials in two ways:

  1. By following the guidance set out in our structured study protocol template. This is the preferred option if you have not yet started writing your manuscript.
  2. By submitting a populated SPIRIT checklist and SPIRIT figure alongside your manuscript. The SPIRIT checklist can be downloaded here or completed using this online tool: The figure must be included in the main body of the text and the checklist must be provided as an additional file. Both the figure and the checklist should be referenced in the text. If any of these elements are missing from the submission, or if the SPIRIT checklist is incomplete (i.e. missing page and line numbers, or a short explanation why an item is not applicable next to each SPIRIT item), the manuscript will be returned to the authors. 

All study protocols for clinical trials are reviewed by a Protocol Editor to ensure that they adhere to our SPIRIT guidance. Please ensure this guidance is followed carefully to prevent delays to the peer review process. For further advice on compliance with the recommendations of the SPIRIT statement, please see: The SPIRIT Checklist—lessons from the experience of SPIRIT protocol editors.

It is understood that for some study protocols certain aspects may not comply fully with each item of the SPIRIT Statement. If used, the checklist will not be used as a tool for judging the suitability of manuscripts for publication in Trials, but is intended as an aid for authors to clearly, completely, and transparently let reviewers and readers know what authors intend to do.  Where an item is not applicable, authors can state this but must also add a brief explanation as to why the item is not applicable. Eg. Biological Specimens, Item no. 33: Not applicable, no samples collected.  Simply saying ’N/A’ will lead to the manuscript being returned. Likewise, if the structured protocol template is used, please follow the guidance by leaving all headings, identifiers and curly brackets in the order given and provide a complete response under each. A complete example can be found here.

The online protocol template called SEPTRE (SPIRIT Electronic Protocol Tool & Resource) is also a web-based option to create, manage, and register protocols using the SPIRIT guidance.

In Review

Authors submitting to Trials can now opt-in to a service called In Review, which provides a pre-print service, meaning the article can be shared with funders and others in a citeable way while it is under review.  It also provides authors with on-demand information on the status of their manuscript, enables them to share their work with funders and others, and allows their wider community to comment and collaborate - all whilst their manuscript is under review. Please see here for full details.

Preparing your manuscript

The information below details the section headings that you should include in your manuscript and what information should be within each section.

Please note that your manuscript must include a 'Declarations' section including all of the subheadings (please see below for more information).

Title page

The title page should:

  • present a title including information about the study design, population, interventions, and, if applicable, trial acronym, using the following format “___________: study protocol for a ___________trial.”
  • list the full names, institutional addresses and email addresses for all authors
    • if a collaboration group should be listed as an author, please list the Group name as an author. If you would like the names of the individual members of the Group to be searchable through their individual PubMed records, please include this information in the “Acknowledgements” section in accordance with the instructions below
  • indicate the corresponding author


The Abstract should not exceed 350 words. Please minimize the use of abbreviations and do not cite references in the abstract. The abstract must include the following separate sections:

  • Background: the context and purpose of the study
  • Methods: how the study will be performed
  • Discussion: a brief summary and potential implications
  • Trial registration: If your article reports the results of a health care intervention on human participants, it must be registered in a WHO ICRTP registry. The name of the registry, registration number and date of registration should all be stated in this section. If it was not registered prospectively (before enrollment of the first participant), you should include the words 'retrospectively registered'. See our editorial policies for more information on trial registration. If your article reports the results of research on research and you have registered your work with the Research on Research (RoR) registry, please include the registry record URL.


Three to ten keywords representing the main content of the article.


The Background section should explain the background to the study, its aims, a summary of the existing literature and why this study is necessary or its contribution to the field.


The methods section should include:

  • the aim, design and setting of the study
  • the characteristics of participants or description of materials
  • a clear description of all processes, interventions, comparisons and details of the randomization process. Generic drug names should generally be used. When proprietary brands are used in research, include the brand names in parentheses
  • the type of statistical analysis used, including a power calculation if appropriate.


This should include a discussion of any practical or operational issues involved in performing the study and any issues not covered in other sections.

Trial status

Authors should report the protocol version number and date, the date recruitment began, and the approximate date when recruitment will be completed.

List of abbreviations

If abbreviations are used in the text they should be defined in the text at first use, and a list of abbreviations should be provided. Please try not to include too many unnecessary acronyms and abbreviations within the text. If this hinders the legibility of the manuscript, you may be asked to remove these by the Editor.


All manuscripts must contain the following sections under the heading 'Declarations':

  • Ethics approval and consent to participate
  • Consent for publication
  • Availability of data and materials
  • Competing interests
  • Funding
  • Authors' contributions
  • Acknowledgements
  • Authors' information (optional)

Please see below for details on the information to be included in these sections. If any of the sections are not relevant to your manuscript, please include the heading and write 'Not applicable' for that section. 

Ethics approval and consent to participate

Trials do not consider study protocols for studies without ethical approval. You will be required to provide a copy of the original ethical approval document and an English translation of this document as an additional file on submission, which will be checked against this declaration. The name of the ethics committee that approved the study and the committee’s reference number (if applicable) should be declared. Details of authors’ intentions to obtain consent to participate in the study from participants (or their parent or legal guardian in the case of children under 16) should be declared. “eg. ABC Ethical Review Board ABC123456. Written, informed consent to participate will be obtained from all participants
More information

Consent for publication

Please do not include any baseline or pilot data in your study protocol. The Editorial Office will ask you to remove this if it is included. If you have included any details, images or videos relating to an individual person, written informed consent for the publication of these details must be obtained from that person (or their parent or legal guardian in the case of children under 18) and declared in this section. Please also state whether you will be willing to provide a model consent form on request. If this section does not apply, please state “Not applicable”.
More information

Availability of data and materials

Please do not include any baseline or pilot data in your study protocol. The Editorial Office will ask you to remove this if it is included. Please declare who will have access to the final trial dataset and disclose contractual agreements that limit such access for investigators.
More information

Competing interests

All financial and non-financial competing interests must be declared in this section. See our editorial policies for a full explanation of competing interests. If you are unsure whether you or any of your co-authors have a competing interest please contact the editorial office. Please use the authors initials to refer to each authors' competing interests in this section. If you do not have any competing interests, please state: "The authors declare that they have no competing interests" in this section.
More information


All sources of funding for the research reported should be declared. You will be required to include a copy of the original funding document and an English translation of this document as an additional file on submission, which will be checked against this declaration. The role of the funding body in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript should be declared.

Authors' contributions

The individual contributions of authors to the manuscript should be specified in this section. Guidance and criteria for authorship can be found in our editorial policies. Please use initials to refer to each author's contribution in this section, for example: "AB is the Chief Investigator; she conceived the study, led the proposal and protocol development. CD contributed to study design and to development of the proposal. EF was the lead trial methodologist. All authors read and approved the final manuscript." Trials welcomes public and patient co-authors. Where a study explicitly mentions patient or public involvement in the design, delivery or dissemination of the study, we would anticipate that there would be at least one patient or public co-author.
More information


Please acknowledge anyone who contributed towards the article who does not meet the criteria for authorship including anyone who provided professional writing services or materials. Authors should obtain permission to acknowledge from all those mentioned in the Acknowledgements section. See our editorial policies for a full explanation of acknowledgements and authorship criteria. If you do not have anyone to acknowledge, please write "Not applicable" in this section. 

Group authorship (for manuscripts involving a collaboration group): if you would like the names of the individual members of a collaboration Group to be searchable through their individual PubMed records, please ensure that the title of the collaboration Group is included on the title page and in the submission system and also include collaborating author names as the last paragraph of the “Acknowledgements” section. Please add authors in the format First Name, Middle initial(s) (optional), Last Name. You can add institution or country information for each author if you wish, but this should be consistent across all authors. Please note that individual names may not be present in the PubMed record at the time a published article is initially included in PubMed as it takes PubMed additional time to code this information.

Authors' information (optional)

This section is optional.
You may choose to use this section to include any relevant information about the author(s) that may aid the reader's interpretation of the article, and understand the standpoint of the author(s). This may include details about the authors' qualifications, current positions they hold at institutions or societies, or any other relevant background information. Please refer to authors using their initials. Note this section should not be used to describe any competing interests.


Footnotes can be used to give additional information, which may include the citation of a reference included in the reference list. They should not consist solely of a reference citation, and they should never include the bibliographic details of a reference. They should also not contain any figures or tables. Footnotes to the text are numbered consecutively; those to tables should be indicated by superscript lower-case letters (or asterisks for significance values and other statistical data). Footnotes to the title or the authors of the article are not given reference symbols. Always use footnotes instead of endnotes.


Examples of the Vancouver reference style are shown below.

See our editorial policies for author guidance on good citation practice

Web links and URLs: All web links and URLs, including links to the authors' own websites, should be given a reference number and included in the reference list rather than within the text of the manuscript. They should be provided in full, including both the title of the site and the URL, as well as the date the site was accessed, in the following format: The Mouse Tumor Biology Database. Accessed 20 May 2013. If an author or group of authors can clearly be associated with a web link, such as for weblogs, then they should be included in the reference.

Example reference style:

Article within a journal

Smith JJ. The world of science. Am J Sci. 1999;36:234-5.

Article within a journal (no page numbers)

Rohrmann S, Overvad K, Bueno-de-Mesquita HB, Jakobsen MU, Egeberg R, Tjønneland A, et al. Meat consumption and mortality - results from the European Prospective Investigation into Cancer and Nutrition. BMC Medicine. 2013;11:63.

Article within a journal by DOI

Slifka MK, Whitton JL. Clinical implications of dysregulated cytokine production. Dig J Mol Med. 2000; doi:10.1007/s801090000086.

Article within a journal supplement

Frumin AM, Nussbaum J, Esposito M. Functional asplenia: demonstration of splenic activity by bone marrow scan. Blood 1979;59 Suppl 1:26-32.

Book chapter, or an article within a book

Wyllie AH, Kerr JFR, Currie AR. Cell death: the significance of apoptosis. In: Bourne GH, Danielli JF, Jeon KW, editors. International review of cytology. London: Academic; 1980. p. 251-306.

OnlineFirst chapter in a series (without a volume designation but with a DOI)

Saito Y, Hyuga H. Rate equation approaches to amplification of enantiomeric excess and chiral symmetry breaking. Top Curr Chem. 2007. doi:10.1007/128_2006_108.

Complete book, authored

Blenkinsopp A, Paxton P. Symptoms in the pharmacy: a guide to the management of common illness. 3rd ed. Oxford: Blackwell Science; 1998.

Online document

Doe J. Title of subordinate document. In: The dictionary of substances and their effects. Royal Society of Chemistry. 1999. of subordinate document. Accessed 15 Jan 1999.

Online database

Healthwise Knowledgebase. US Pharmacopeia, Rockville. 1998. Accessed 21 Sept 1998.

Supplementary material/private homepage

Doe J. Title of supplementary material. 2000. Accessed 22 Feb 2000.

University site

Doe, J: Title of preprint. (1999). Accessed 25 Dec 1999.

FTP site

Doe, J: Trivial HTTP, RFC2169. (1999). Accessed 12 Nov 1999.

Organization site

ISSN International Centre: The ISSN register. (2006). Accessed 20 Feb 2007.

Dataset with persistent identifier

Zheng L-Y, Guo X-S, He B, Sun L-J, Peng Y, Dong S-S, et al. Genome data from sweet and grain sorghum (Sorghum bicolor). GigaScience Database. 2011.

Figures, tables and additional files

See General formatting guidelines for information on how to format figures, tables and additional files.

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