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These articles should report original research relevant to clinical medicine in a way that is accessible to readers of a general journal. This editorial explains what kind of research we give priority to, and what services we offer to authors of research: Why submit your research to the BMJ?
Original research articles should follow the IMRaD style (introduction, methods, results and discussion) and should have a structured abstract and a structured discussion.
No word limit
We do not set fixed limits for the length of BMJ research articles and can be flexible. We produce abridged versions of research articles in the printed BMJ while publishing their full versions on bmj.com. Nonetheless, 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.
What other information do we need?
Please see our requirements for all BMJ manuscripts which give full details of what you should include with all manuscripts. For original research articles in particular, please note that we need, as appropriate:
If any of this information (except GRADE) is missing we will require it before we can send your article for external review.
These and other reporting guidelines are collected together in one place: the website of the EQUATOR network. This network seeks to improve the quality of scientific publications by promoting transparent and accurate reporting of health research.
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. Please include in the results section of your structured abstract (and, of course, in the article's results section) the following terms, as appropriate:
For a clinical trial:
For a cohort study:
For a case control study:
For a study of a diagnostic test:
The box stating what is known and what this paper adds (see below) should also reflect accurately the above information. Under what this paper 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.
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. Please note the general rules for abstracts in the BMJ:
The first few items (objective, design, setting) may be note-like and need not form full sentences. The results and conclusions sections should be written properly. Do not mix notes and full sentences in one section.
If the standard headings do not suit the type of study, 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:
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:
Abstracts for qualitative research articles should follow the standard style but may need fewer headings:
Quality improvement reports also have their own style of structured abstract:
Please ensure that the discussion section of your article follows this structure:
“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 It 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 provided evidence of higher methodological quality for a message which is already known.
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.
If you are sending us a revised article
Please provide all of the above (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.
We often publish original research articles with an accompanying 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 BMJ article you are commenting on and give its BMJ registration number.