• Open peer review
  • Open access
  • Open access institutional memberships
  • Trial registration
  • Registration of other studies - particularly observational studies
  • The BMJ's policy on drug and devices trials
  • Industry sponsored studies
  • Data sharing
  • Patients' involvement in research
  • Data sharing statement
  • How to prepare original research articles (full versions) for The BMJ
  • BMJ Research to Publication elearning programme for health researchers
  • The BMJ’s Impact Factor is 20.7 (ISI Web of Science, 2017).

    Articles should be submitted as "Research" via our online editorial office. As it is not always possible for us to answer presubmission inquiries, this advice may help you decide whether The BMJ is the right journal for your research. This editorial explains what kind of research we are looking for and give priority to, and these tips may help with your decision.

    The BMJ welcomes studies that were led or coauthored by patients and in all papers we ask authors to state if and how patients were involved in formulating the research question, and designing and/ or conducting the research. Find more information on how to do this here.

    Research articles should report original research studies that can improve decision making in medical practice, policy, education, or research and will be understandable by general medical readers. We welcome studies - even with "negative" results - as long as their research questions are important, new, and relevant to general readers and their designs are appropriate and robust.

    Please note that we do not usually accept case series or qualitative research.

    Case series lack formal hypotheses and formal study designs that prespecify the sampling criteria and methods, data collection, and analyses. If they had all these things they would be cohort studies.

    Hence a case series is rarely the best design to answer a research question, particularly when describing clinical experience with an intervention. Even when that intervention is the clinical and/or practical response to an event or a disease outbreak, the case series has scientific limitations and allows few generalisable or actionable conclusions to be drawn. A series - even if compared with a control group - cannot answer questions about appropriateness, effectiveness, and adverse effects.

    At the early stages of the response to an unusual major event or disease outbreak, however, case series can provide helpful and original preliminary information for clinicians and policy makers. So The BMJ will consider as research articles case series that are sufficiently informative for clinical and public health practice or policy (preferably internationally) and are compelling, well described, and topical.

    When such a series raises controversial issues for health services and policy, warranting detailed description and discussion, an analysis article might be the best format.

    Qualitative studies: The BMJ does not publish preliminary, exploratory studies with limited generalisability, and this often rules out much qualitative research. Although we appreciate that qualitative studies can yield very interesting insights and questions, they don't provide firm answers and hence have limited potential to improve doctors' decisions. Our data show that most of the qualitative research we have published is rarely downloaded, shared, cited, or picked up in other ways by readers. Moreover, we're increasingly prioritising papers that will be relevant to our wide international audience, as explained in this editorial, and a lot of qualitative work tends to be very specific to its own setting.

    All research studies published in The BMJ should be morally acceptable, and must follow the World Medical Association's Declaration of Helsinki. To ensure this, we aim to appraise the ethical aspects of any submitted work that involves human participants, whatever descriptive label is given to that work including research, audit, and sometimes debate. This policy also applies on the very rare occasions that we publish work done with animal participants.

    To learn more about the kind of research we give priority to, and what services we offer to authors of research, please read this editorial.

    Open peer review

    We ask all reviewers, both peer and patient to sign their reports and declare any competing interests on any manuscripts we send them. Reviewers advise the editors, who make the final decision (aided by an editorial manuscript committee meeting for some articles, including original research).

    For research papers, The BMJ has fully open peer review. This means that accepted research papers submitted from September 2014 onwards will usually have their prepublication history posted alongside them on (read more in this editorial).

    Open access

    All research papers in the BMJ are published with open access. Moreover, The BMJ immediately fulfils the requirements of the US National Institutes of Health, the UK Medical Research Council, the Wellcome Trust, and other funding bodies by making the full text of publicly funded research freely available to all on and sending it directly to PubMed Central, the National Library of Medicine's full text archive.

    Open access articles may be reused according to the relevant Creative Commons licence. The BMJ's default licence for open access publication of research is the Creative Commons Attribution Non Commercial licence (CC BY-NC 4.0). But where the funder requires it the author can select the Creative Commons Attribution (CC BY 4.0) licence during the submission process (funders who mandate CC BY include the Wellcome Trust, RCUK, and MRC). In brief: users are free to share and adapt open access articles as long as the original work is attributed and the reuse in no way suggests that the author or publisher endorses their use of the work. There are restrictions on commercial use for articles published under CC BY-NC.

    The BMJ is committed to keeping research articles open access. To support this we ask authors to pay an open access article publishing charge/fee of £3000 (excluding VAT) on acceptance of their paper. We can offer discounts and waivers for authors who cannot pay. Consideration of the paper is not related to whether authors can or cannot pay the fee. We will ask for the fee only once we have accepted a paper, and we will send an invoice only once authors tell us (via they can claim the fee. Seeking and processing fees will not delay editing or publication. Please do not contact editors about open access fees: neither editors nor reviewers will know whether a fee is payable, and administrative staff will handle payments and all associated correspondence.

    Open access institutional memberships

    A number of institutions have open access institutional memberships with BMJ (the publishing group), which either cover the whole cost of open access publishing for authors at participating institutions or allows authors to receive a discount on the article processing charge. For a list of member institutions and their policies on how to receive a discount or to publish free of charge, please visit

    Trial registration

    In accordance with the International Committee of Medical Journal Editors' Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals (ICMJE Recommendations 2013), The BMJ will not consider reports of clinical trials unless they were registered prospectively before recruitment of any participants. Failure to register clinical trials prospectively is a breach of research ethics and contravenes the Declaration of Helsinki. When The BMJ receives an article about a clinical trial that was not prospectively registered the editors may inform the bodies that approved and supported the trial, so that these bodies can monitor and ensure compliance. We may contact trial sponsors and funders as well as ethics committees/institutional review boards.

    This policy on prospective registration to trials which started after 1 July 2005: for older trials retrospective registration will be acceptable, but only if completed before submission of the manuscript to the journal.

    Eligible trials have been defined by ICMJE since 1 July 2008 as trials "where human participants are prospectively assigned to one or more health-related interventions (including health services and behavioural interventions) to evaluate the effects on health outcomes," and before that were defined more narrowly as trials "where human participants are prospectively assigned to investigate the cause and effect relationship between a medical intervention and health outcome."

    This means that:

    • Trials randomising human participants to investigate the cause and effect relation between a medical intervention and a health outcome that started before 1 July 2005 can be registered retrospectively, but this must be done before submission to The BMJ.
    • Trials randomising human participants to investigate the cause and effect relation between a medical intervention and a health outcome that started after 1 July 2005 must have been registered prospectively, ie before enrolment of any participants.
    • Trials randomising human participants or groups of humans to one or more health-related interventions (including health services and behavioural interventions) to evaluate the effects on health outcomes and that started after 1 July 2008 must have been registered prospectively, ie before enrolment of any participants.*

    * Please note that ICMJE says: " Some trials assign healthcare providers, rather than patients, to intervention and comparison/control groups. If the purpose of the trial is to examine the effect of the provider intervention on the health outcomes of the providers’ patients, then investigators should register the trial. If the purpose is to examine the effect only on the providers (for example, provider knowledge or attitudes), then registration is not necessary."

    The BMJ's criteria for a suitable public trial registry are: it is free to access, searchable, and identifies trials with a unique number; registration is free or has minimal cost; registered information is validated; registered entry includes details to identify the trial and investigator and includes the status of the trial; and the research question, methodology, intervention, funding, and sponsorship must all be disclosed at registration.

    The BMJ does not consider posting of protocols and results in clinical trial registries to be prior publication.

    The ethical and scientific arguments for trial registration were defined in the Ottawa Statement, 2005:

    Registration of other studies - particularly observational studies

    There are no fixed rules about the registration of studies or about the use and provision of study protocols, other than for clinical trials. However, The BMJ actively supports the registration of protocols and results in publicly accessible registries for all types of study involving human participants, particularly observational studies.

    Observational studies, such as cohort and case-control studies, are an important form of medical research but they are vulnerable to bias and selective reporting. When an observational study is submitted to the BMJ we will ask authors for:

    • The registration details, if the study has been registered - these should be added to the last line of the paper's abstract. We will also ask for claification about whether the study was registered before data acquisition or analysis began.
    • The protocol, if one exists - uploaded as a supplemental file to the submitted paper.
    • A clear statement of whether the study hypothesis arose before or after inspection of the data (and, if afterwards, we will need an explanation of steps taken to minimise bias).
    • A completed STROBE checklist - uploaded as a supplemental file to the submitted paper. We will pay particular attention to these items which ask authors to "explain the scientific background and rationale for the investigation being reported" and "state specific objectives, including any prespecified hypotheses."

    We appreciate that many new ideas arise from unexpected findings in observational research, and we aim to apply the above policy in a flexible manner. Hence we will not necessarily reject an observational study just because it did not have a prespecified hypothesis, but if it did not we will want the exploratory nature of its research question, and its design, to be fully reported. However The BMJ gives highest priority to studies that provide strong support for inferences applicable to clinical practice, and we think the case against data driven observational studies is particularly compelling under these circumstances.

    The BMJ's policy on drug and devices trials

    We welcome submission of any drug or device trial that asks an original research question that will sufficiently aid doctors' decisions.

    Since January 2013, we have considered trials of drugs and medical devices for publication only if the authors commit to making the relevant anonymised patient level data available on reasonable request (see editorial). This policy applies to any research article that reports the main endpoints of a randomised controlled trial of one or more drugs or medical devices in current use, whether or not the trial was funded by industry.

    “Relevant data” encompasses all anonymised data on individual patients on which the analysis, results, and conclusions reported in the paper are based. As for “reasonable request,” The BMJ is not in a position to adjudicate, but we will expect requesters to submit a protocol for their re-analysis to the authors and to commit to making their results public. We will encourage those requesting data to send a rapid response to, describing what they are looking for. If the request is refused we will ask the authors of the paper to explain why.

    Other requirements: please also provide the trial registration details, the relevant completed CONSORT checklist, a completed TIDieR checklist if appropriate, and the original study protocol for use in confidence during peer review (or a revised protocol along with explanation of the revisions). Please declare the details of all sources of funding for the study; provide statements of competing interests and contributorship; fully describe the role of the study sponsors; provide a statement on the independence of researchers from funders; and state whether all authors had full access to and can take responsibility for the data and analyses. All of these items are explained in more detail in the general advice about research articles, below.

    Which drug and device trials does The BMJ prioritise?

    • We give highest priority to trials of the comparative effectiveness of drugs or devices or other interventions head to head against the best current treatment(s) using clinically valid doses/administration of both study and comparator interventions.
    • Placebo controlled trials often have much more limited relevance to practice than head to head trials and may not sufficiently help The BMJ's readers' decisions, but we are willing to consider these too if the research questions are sufficiently important and clearly explained.

    In addition, we will give greater priority to a drug or device trial if it:

    • Is reported fully in line with the CONSORT statement or the relevant CONSORT extension statement (eg for cluster randomised trials), and has sufficient internal and external validity.
    • Is reported transparently, as explained in our detailed advice below on reporting industry-sponsored trials, and particularly in line with the Good Publication Practice (GPP2) guidelines.
    • Is a phase III trial.

    Industry sponsored studies

    If you are submitting an original article reporting an industry sponsored clinical trial, postmarketing study, or other observational study please follow the guidelines on good publication practice (GPP2) and on properly reporting the role of professional medical writers. Another resource, the Authors' Submission Toolkit: A practical guide to getting your research published summarises general tips and best practices to increase awareness of journals' editorial requirements, how to choose the right journal, submission processes, publication ethics, peer review, and effective communication with editors - much of which has traditionally been seen as mysterious to authors.

    The BMJ's policy on studies funded by the tobacco industry

    The BMJ will not consider for publication any study that is partly or wholly funded by the tobacco industry, as explained in this editorial.

    Data sharing

    We will consider reports of randomised trials for publication only if the authors commit to making the relevant anonymised patient level data available on reasonable request (see editorial for further explanation). This policy applies to any research article that reports the outcomes of a randomised controlled trial of any type of intervention.

    For all research articles: we encourage authors of all research articles in The BMJ - whether reporting randomised trials or other study types - to link their articles to the raw data from their studies. For clinical trials, we require data sharing on request as a minimum - if authors of such trials are willing to go further and share the data openly, so much the better.

    The BMJ has partnered with the Dryad digital repository to make open deposition easy and to allow direct linkage by doi from the dataset to The BMJ's article and back (for The BMJ's articles' datasets see here)

    Why share data? We are keen to maximise the usefulness and usage of data and promote transparency, and to satisfy the requirements of the many research funders that encourage or even mandate data sharing.

    Confidentiality and consent: we recommend that researchers should seek informed consent to data sharing from research participants upfront, at the recruitment stage.

    Consent is particularly important because participants may be identifiable in a dataset - even an "anonymised" one that does not contain names or addresses. The combination of three or more indirect identifiers such as age, sex, and an unusual clinical detail may be enough for at least the participant, or another interested party, to recognise themselves.

    Reporting patients' involvement in research

    As part of its patient partnership strategy, the BMJ is encouraging active patient involvement in setting the research agenda.

    We appreciate that not all authors of research papers will have done this, and we will still consider your paper if you did not involve patients at an early stage. We do, however, request that all authors provide a statement in the methods section under the subheading Patient involvement.

    This should provide a brief response to the following questions:

    • How was the development of the research question and outcome measures informed by patients’ priorities, experience, and preferences?
    • How did you involve patients in the design of this study?
    • Were patients involved in the recruitment to and conduct of the study?
    • How will the results be disseminated to study participants?
    • For randomised controlled trials, was the burden of the intervention assessed by patients themselves?

    Patient advisers should also be thanked in the contributorship statement/acknowledgements.

    If patients were not involved please state this.

    If this information is not in the submitted manuscript we will ask you to provide it during the peer review process.

    Please also note also note that The BMJ now sends randomised controlled trials and other relevant studies for peer review by patients.

    Data sharing statement

    We require a data sharing statement at the end of every research manuscript. For trials of drugs or devices the statement must state, at a minimum, that the the relevant anonymised patient level data are available on reasonable request from the authors.

    Options for formatting the statement are suggested here:

    "Data sharing: patient level data [and/or] full dataset [and/or] technical appendix [and/or] statistical code [and/or] available at [/doi] [with open access/with these restrictions] [from the corresponding author at ]. Participants gave informed consent for data sharing [or ... consent was not obtained but the presented data are anonymised and risk of identification is low ... or consent was not obtained but the potential benefits of sharing these data outweigh the potential harms because ...]"

    If no such further data are available, please use this wording: "Data sharing: no additional data available." This option is not available for trials of drugs or devices.

    How to prepare original research articles (full versions) for The BMJ

  • No word limit
  • Abridged research articles
  • Video abstracts
  • Title page
  • Overall style
  • Structured abstract
  • Structured discussion
  • What other information do we need?
  • "What this paper adds" box
  • Summary statistics to clarify your message
  • If you are sending us a revised article
  • Commentaries on research
  • No word limit

    To encourage full and transparent reporting of research we do not set fixed limits for the length of research articles in The BMJ. None the less, please try to make your article concise and make every word count. Think hard about what really needs to be in the paper to get your message across accurately and what can be left out. We suggest 4400 words as a guideline for fully reporting a study's methods (including Patient involvement), results, introduction, and discussion in an average article, although we recognise that some studies may need more space, others less. You will be prompted to provide the word count for the main text (excluding the abstract, references, tables, boxes, or figures) when you submit your manuscript.

    Important: The manuscript should include the structured abstract and all tables, figures, boxes, and appendices that are essential to reporting the study design and findings. We may suggest later that you separate out some material into web extras to make the main manuscript clearer for general readers, but for peer review (including editorial and statistical review), the manuscript should be a complete document that fully reports the study.

    Abridged research articles

    The full text of all accepted research articles in The BMJ is published online in full, with open access and no word limit, on as soon as it is ready. In the print issue of The BMJ, each research article is abridged, with the aim of making research more inviting and useful to readers.

    The BMJ's structured abstract is our abridged format for research papers in the print journal. We designed the structured abstract with experts in evidence based medicine, to succinctly present the key evidence from each study, to help minimise delay between online and print publication, and to enable us to publish more research in each week's print issue of The BMJ.

    Video abstracts

    We welcome video abstracts lasting up to 4 minutes to accompany accepted research articles in The BMJ. These enable authors to go beyond the constraints of their written article, to personally explain the importance of their work to The BMJ's global audience. Video abstracts present the research question and main findings of the study in an accessible way, to improve the audience’s understanding and appreciation of the work, and to facilitate and increase readership of the article.

    In the simplest kind of video abstract, the author(s) talk directly to the camera and, perhaps, presents a slideshow. In the interest of maximising engagement and visibility, however, we encourage authors, where appropriate, to combine footage of themselves with other relevant visual and audio material (such as animations, video clips showing how the study was conducted and any intervention was delivered, audio, still photographs, figures, infographics). If they wish to use material from previously published work authors will need to show The BMJ that they have appropriate permissions from the relevant publisher(s).

    We publish our video abstracts in two places: embedded within the research article on, and separately on our YouTube channel. For examples see the video abstract collection on our multimedia page.

    There are many tutorials online that can guide the production of a video abstract, using widely and often freely available software. Windows Movie Maker and Apple iMovie are the most common examples. Below are a few guidelines for making a video abstract, but if you have any questions about how best to produce them, please contact Duncan Jarvies (, multimedia producer for The BMJ.

    Please follow these basic guidelines when producing a video abstract:

    1. Video abstracts should not be any longer than 4 minutes.
    2. A video abstract should be based on the revised abstract that you’ll have already been asked to create. The content and focus of the video must relate directly to the study that has been accepted for publication by The BMJ and should not stray beyond the data.
    3. The presentation and content of the video should be in a style and in terms that will be understandable and accessible to a general medical audience. The main language should be English, but we welcome subtitles in another language. Please avoid jargon that will not be familiar to a wide medical audience, and do not use abbreviations.
    4. We strongly encourage inclusion of additional relevant material such as images, animations and/or clinical footage.
    5. If the video shows any identifiable living patients and/or gives anyone’s identifiable personal details, we will require consent, using The BMJ's standard patient consent form. Please ensure that the video abstract complies with the The BMJ’s policy on patient confidentiality.
    6. When delivering video to us, please use the compression parameters that video sharing sites use. Often these are standard options from your editing software. A comprehensive "how to" page is available from the Vimeo website.
    7. Terms and conditions regarding the use and distribution of video abstracts will apply in line with The BMJ’s policy on research – that is Creative Commons, free to view and distribute.

    PLEASE NOTE: All video abstracts will be assessed for suitability by The BMJ's editorial team.

    Title page

    This should give the title of the article, including the study design. Please give for each author his or her name and initials, full address including postal code and one main work position (job title) at the time of writing the paper. We do not need authors’ qualifications. For the corresponding author please provide an email address and the best contact address: this may differ from his or her work address.

    Please check the list of authors carefully to be certain that it is complete and in the correct order. As a general rule, we will not allow changes to the author list once a paper has been submitted. The BMJ has an open peer review process. Reviewers and editors know the names of a paper's authors and are able to judge the work in light of the authors' conflicts of interest. If authors are added or removed after the evaluation is done, that process is subverted. In that case, we reserve the right to withdraw acceptance and submit the paper to additional peer review.

    If the number of authors is very large we may ask for confirmation that everyone listed met the ICMJE criteria for authorship. If they did, we reserve the right to require the formation of an authorship group whose name will appear in the article byline. MEDLINE guidance explains that group authorship is acceptable, stating "When a group name for a specific consortium, committee, study group, or the like appears in an article byline, the personal names of the members of that group may be published in the article text. Such names are entered as collaborator names for the MEDLINE citation."

    Overall style

    Original research articles should follow the IMRaD style (introduction, methods, results, and discussion) and should include a structured abstract (see below), a structured discussion, and a succinct introduction that focuses - in no more than three paragraphs - on the background to the research question.

    This video slideshow presentation gives more detailed advice on writing each section of a research paper for The BMJ.

    Please report statistical aspects of the study in line with the "Statistical Analyses and Methods in the Published Literature (SAMPL) Guidelines." We also ask you to ensure that the manuscript includes all the information recommended in the relevant reporting statement, for example CONSORT. Research reporting guidelines and statements, such as CONSORT, are all available in one place on the website of the EQUATOR network. We do not use reporting guidelines as critical appraisal tools to evaluate study quality or filter out articles. We're simply aiming to make research articles so clear that peer reviewers, editors, clinicians, educators, ethicists, policy makers, systematic reviewers, guideline writers, journalists, patients, and the general public can tell what really happened during a study.

    Structured abstract

    Please scroll down for detailed advice on preparing this.

    Structured discussion

    Please ensure that the discussion section of your article comprises no more than five paragraphs and follows this overall structure, although you do not need to signpost these elements with subheadings:

    • Statement of principal findings
    • Strengths and weaknesses of the study
    • Strengths and weaknesses in relation to other studies, discussing important differences in results
    • Meaning of the study: possible explanations and implications for clinicians and policymakers
    • Unanswered questions and future research

    What other information do we need?

    Please see our general requirements for all manuscripts for The BMJ. For original research articles in particular, please note that we need, as appropriate:

    In the manuscript

    • For an intervention study the manuscript should include enough information about the intervention(s) and comparator(s) (even if this was usual care) for reviewers and readers to understand fully what happened in the study. To enable readers to replicate your work or implement the interventions in their own practice, please also provide any relevant detailed descriptions and materials (uploaded as one or more supplemental files, including video and audio files where appropriate). Alternatively, please provide in the manuscript URLs to openly accessible websites where these materials can be found.

    • A Patient involvement statement. This is best placed at the bottom of the Methods section.

    • A declaration of competing interests. This should be composed after each author has filled in the International Committee of Medical Journal Editors' Unified Competing Interest form, and the corresponding author should keep the completed forms in case they are required later. Please then add to the manuscript a statement in the following format:

      Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organisation for the submitted work [or describe if any]; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years [or describe if any]; no other relationships or activities that could appear to have influenced the submitted work [or describe if any] .”

    • Details of contributors - giving their names and specific roles - and the name of the guarantor(s) for the study. Please consider including your public and patient involvement volunteers and your study participants when this is applicable.
    • A statement that any identifiable patients have provided their signed consent to publication. Please submit, as a supplemental file, The BMJ's patient consent form, with your signature, giving consent to publication in The BMJ of any information about identifiable individual patients. Publication of any personal information about a patient in The BMJ - for example, in a case report or clinical photograph - will normally require the signed consent of the patient.
    • A statement that the study obtained ethics approval (or a statement that it was not required), including the name of the ethics committee(s) or institutional review board(s), the number/ID of the approval(s), and a statement that participants gave informed consent before taking part.
    • A statement giving the details of all sources of funding for the study.
    • A description of the role of the study sponsor(s) or funder(s), if any, in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.
    • A statement of the independence of researchers from funders.
    • A statement that all authors, external and internal, had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis.
    • A transparency declaration: a statement that the lead author (the manuscript's guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
    • A data sharing statement such as "Data sharing: patient level data [and/or] full dataset [and/or] technical appendix [and/or] statistical code [and/or] available at [/doi] [with open access/with these restrictions] [from the corresponding author at ]. Participants gave informed consent for data sharing [or ... consent was not obtained but the presented data are anonymised and risk of identification is low ... or consent was not obtained but the potential benefits of sharing these data outweigh the potential harms because ...]". If no such further data are available, please use this wording: "Data sharing: no additional data available."
    • A trial registration number and name of register for a clinical trial—in the last line of the structured abstract.
    • A registration number and name of register for any study type, if registered—in the last line of the structured abstract. We are keen to promote registration for observational studies and systematic reviews.
    • For articles that include explicit statements of the quality of evidence and strength of recommendations, we prefer reporting using the GRADE system (we encourage, but do not insist on, this).
    • One or more references for the statistical package(s) used to analyse the data - for example, RevMan for a systematic review. There is no need to provide a formal reference for a very widely used package that will be familiar to general readers - for example, Stata - but please say in the text which version you used.

    As supplemental files

    • The original protocol for a clinical trial or, if the protocol has been published in an open access online journal, its reference and URL. We appreciate that studies sometimes deviate from protocols, but please explain any important deviations in the manuscript, particularly those about choice of outcomes and analyses or change in sample size.
    • The original protocol for an observational study or systematic review, if available. We recommend that protocols for randomised trials are written using the SPIRIT checklist.
    • For a randomised controlled trial, the appropriate completed CONSORT checklist showing on which page of your manuscript each checklist item appears, the CONSORT-style structured abstract, and the CONSORT flowchart (CONSORT has several extension statements - for example, for cluster RCTs, pragmatic trials).
    • For a randomised controlled trial, a completed TIDieR checklist - this helps to ensure that trial interventions are fully described in ways that are reproducible, usable by other clinicians, and clear enough for systematic reviewers and guideline writers.
    • PRISMA checklist and flowchart for a systematic review or meta-analysis of randomised trials and other evaluation studies.
    • STARD checklist and flowchart for a study of diagnostic accuracy.
    • STROBE checklist for an observational study.
      Please use the STROBE extensions, where appropriate:

    • TRIPOD statement for studies reporting clinical prediction models.
    • GRIPS for genetic risk prediction studies.
    • CHEERS for an economic evaluation.
    • Original raw data if you think they will help our reviewers (and maybe readers), or if we specifically request them. Please note our policy on data sharing, explained above
    • Video and audio files that will add educational value to your article, for example by explaining the intervention in a trial.
    • Public and patient involvement materials used in your research.
    • Copies of any non-standard questionnaires and assessment schedules used in the research.
    • Copies of patient information sheets used to obtain informed consent for the study or to comprise or deliver the intervention in a clinical trial.
    • Copies of closely related articles you have published (this is particularly important when details of the study methods are published elsewhere).
    • Copies of any previous reviewers' reports on this article. We appreciate that authors may have tried other journals before sending their work to The BMJ, and find it helpful if you let us know how you have responded to previous reviewers' comments.

    In the cover letter

    • Details of previous publications from the same study - including in scientific abstracts or partial reports by the media at scientific meetings and in foreign language journals.
    • Details of any previous publication of the same study in electronic form. For example, The BM does not consider posting of protocols and results in clinical trials registries to be prior publication, but we would like to know if results have been posted, and where (please provide URLs or trial registration details). And we are pleased to consider articles based on longer systematic reviews and meta-analyses published at the Cochrane Library or HTA database.
    • Names and contact details (including email addresses) of suitable peer reviewers; we often find authors' suggestions helpful, although this is optional.
    • Assurance that a study funded or sponsored by industry follows the guidelines on good publication practice. These GPP2 guidelines aim to ensure that such studies are published in a responsible and ethical manner. The guidelines cover companies’ responsibility to endeavour to publish results of all studies, companies’ relations with investigators, measures to prevent redundant or premature publication, the roles of authors and contrbutors, and the role of professional medical writers.
    • Assurance that any article written by a professional medical writer follows the guidelines by the European Medical Writers' Association on the role of professional medical writers. The guidelines emphasise the importance of respecting widely recognised authorship criteria, and in particular of ensuring that all people listed as named authors have full control of the content of articles. The role of professional medical writers must be transparent. Please name any professional medical writer among the list of contributors to any article for the BMJ (not only original research articles), and specify in the formal funding statement for the article who paid the writer. Writers and authors must have access to relevant data while writing articles. Medical writers have professional responsibilities to ensure that the articles they write are scientifically valid and are written in accordance with generally accepted ethical standards.

    Structured abstract

    Please note that as of 24 October 2015, The BMJ underwent a substantial print redesign. We have dispensed with the Pico summary, and now use restructured abstracts that will appear in the print issue only. Please note that the definitive, online version of the full length article will still have abstracts structured as set out in the guidelines below.

    With the new print abstract structure, we hope to merge the best components of the Pico and the online abstract to present the information in a succinct and readable format. We will update this section in due course, but for more details please see this editorial.

    Please ensure that the structured abstract is as complete, accurate, and clear as possible—but not unnecessarily long—and has been approved by all authors. We may screen original research articles by reading only the abstract. For randomised controlled trials please provide all the information required for the CONSORT extension for abstracts.

    Please note the general rules for abstracts in The BMJ:

    • Abstracts should be 250- 300 words long: you may need up to 400 words, however, for a CONSORT or PRISMA style abstract. MEDLINE can now handle up to 600 words
    • Use active voice but avoid “we did” or “we found”.
    • Numbers over 10 do not need spelling out at the start of sentences.
    • Sentences starting with a number do not require a capital letter.
    • P values should always be accompanied by supporting data, and denominators should be given for percentages.
    • Abstracts do not need references.

    If the standard headings do not suit the type of study, please substitute something sensible, such as "population" as a heading instead of "participants" in an economics article. Please do not simply delete the heading.

    For standard original research articles please provide the following headings and information (for RCTs please add the trial registration details - but there is no need to provide the additional subheadings which are used in the CONSORT statement on abstracts, as long as you include all the required information, and the same applies to the PRISMA statement):

    • Objectives - a clear statement of the main aim of the study and the major hypothesis tested or research question posed
    • Design - including factors such as prospective, randomisation, blinding, placebo control, case control, crossover, criterion standards for diagnostic tests, etc.
    • Setting - include the level of care, eg primary, secondary; number of participating centres. Be general rather than give the name of the specific centre, but give the geographical location if this is important.
    • Participants (instead of patients or subjects) - numbers entering and completing the study, sex, and ethnic group if appropriate. Give clear definitions of how selected, entry and exclusion criteria.
    • Interventions - what, how, when and for how long. This heading can be deleted if there were no interventions but should normally be included for randomised controlled trials, crossover trials, and before and after studies.
    • Main outcome measures - those planned in the protocol, those finally measured (if different, explain why).
    • Results - main results with (for quantitative studies) 95% confidence intervals and, where appropriate, the exact level of statistical significance and the number need to treat/harm. Whenever possible, state absolute rather than relative risks.
    • Conclusions - primary conclusions and their implications, suggesting areas for further research if appropriate. Do not go beyond the data in the article. Conclusions are important because this is often the only part that readers look at.
    • Trial registration - registry and number (for clinical trials and, if available, for observational studies and systematic reviews).

    Please note that confidence intervals should be written in the format (15 to 27) within parentheses, using the word "to" rather than a hyphen.

    Abstracts for meta-analyses and systematic reviews should have these headings but should also include all the items required (as recommended in the PRISMA statement):

    • Objective - what the review set out to determine.
    • Design - type of meta-analysis, systematic review and study appraisal and synthesis methods.
    • Data sources - where included studies were retrieved from.
    • Eligibility criteria for selecting studies - inclusion and exclusion criteria (specifying participants and interventions, as appropriate).
    • Results - main findings with 95% confidence intervals.
    • Conclusions - primary conclusions and their implications.
    • Systematic review registration - registry and number (if registered.

    Quality improvement reports - which are published in The BMJ's Practice section - also have their own style of structured abstract:

    • Problem
    • Design
    • Setting
    • Key measures for improvement
    • Strategies for change
    • Effects of change
    • Lessons learnt

    "What this paper adds" box

    Please produce a box offering a thumbnail sketch of what your article adds to the literature, for readers who would like an overview without reading the whole article. The box should be divided into two short sections, each with 1-3 short sentences.

    Section 1: What is already known on this subject

    In two or three single sentence bullet points, please summarise the state of scientific knowledge on this subject before you did your study, and why this study needed to be done. Be clear and specific, not vague.

    For example, you might say: “Numerous observational studies have suggested that tea drinking may be effective in treating depression, but until now evidence from randomised controlled trials has been lacking/the only randomised controlled trial to date was underpowered/was carried out in an unusual population/did not use internationally accepted outcome measures/used too low a dose of tea.”

    or: “Evidence from trials of tea therapy in depression have given conflicting results. Although Sjogren and Smith conducted a systematic review in 1995, a further 15 trials have been carried out since then…”

    Section 2: What this study adds

    In one or two single sentence bullet points, give a simple answer to the question “What do we now know as a result of this study that we did not know before?” Be brief, succinct, specific, and accurate. For example: "Our study suggests that tea drinking has no overall benefit in depression."

    You might use the last sentence to summarise any implications for practice, research, policy, or public health. For example, your study might have asked and answered a new question (one whose relevance has only recently become clear); contradicted a belief, dogma, or previous evidence provided a new perspective on something that is already known in general; or provided evidence of higher methodological quality for a message that is already known.

    Summary statistics to clarify your message

    We do want your piece to be easy to read but also want it to be as scientifically accurate as possible. Whenever possible, state absolute rather than relative risks. Please include in the results section of your structured abstract (and in the article's results section) the following terms, as appropriate:

    For a clinical trial:

    • Absolute event rates among experimental and control groups.
    • RRR (relative risk reduction).
    • NNT or NNH (number needed to treat or harm) and its 95% confidence interval (or, if the trial is of a public health intervention, number helped per 1000 or 100,000).

    For a cohort study:

    • Absolute event rates over time (eg 10 years) among exposed and non-exposed groups
    • RRR (relative risk reduction)

    For a case control study:

    • OR (odds ratio) for strength of association between exposure and outcome

    For a study of a diagnostic test:

    • Sensitivity and specificity
    • PPV and NPV (positive and negative predictive values)

    The box stating what is known and what this study adds (see below) should also reflect accurately the above information. Under what this study adds, please give the one most useful summary statistic eg NNT.

    Please do not use the term "negative" to describe studies that have not found statistically significant differences, perhaps because they were too small. There will always be some uncertainty, and we hope you will be as explicit as possible in reporting what you have found in your study. Using wording such as "our results are compatible with a decrease of this much or an increase of this much" or "this study found no effect" is more accurate and helpful to readers than "there was no effect/no difference." Please use such wording throughout the article, including the structured abstract and the box stating what the paper adds.

    If you are sending us a revised article

    Please provide all of the above, as appropriate (if not done earlier), as well as a detailed covering letter explaining how you have responded to editorial and peer review comments and other guidance from The BMJ. All of this should be submitted via your author area at our online editorial office.

    Commentaries on research

    We often commission editorials linked to accepted research articles. From time to time we may publish original research articles with an accompanying online commentary of up to 500 words and five references, commissioned to help readers interpret the research or place it in context. If we commission a commentary on your article we will send you a copy of it before publication.

    If we ask you to write a commentary, please provide in the manuscript a title for your piece; a title page giving your name, position, and contact details including email address; and statements of competing interests and - if appropriate - contributorship and funding. Please say in your covering letter or email which article in The BMJ you are commenting on and give its BMJ manuscript number.