Original research

Up to 4,000 words with a maximum of five tables and figures and 30 references using the Vancouver style; there must be a structured abstract of no more than 250 words and the paper will usually be organised using the Abstract, Introduction, Methods, Results and Discussion (AIMRAD) structure. The context of the words and your choice of methods used for analysis must be clear in the text. Qualitative and quantitative research are welcomed equally; summary points* should be included in a box in the text.

Review articles: up to 5,000 words worth more freedom on the number of references; summary points* should be included in a box in the text.

Discussion papers: up to 3,500 words with up to two tables/figures; summary points* should be included in a box in the text.

Commentaries: up to 1,000 words and no more than 10 references.

Short Reports: up to 1,000 words and one table or figure; 5 references.

Letters to the Editor: up to 500 words.

*Summary points (3-5 bullet points) summarising the key messages of the paper should be provided for review and reference.

Title page

This should give the title of the paper, including the study design if the paper presents original research. Please give for each author his or her name and initials, postal address 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.

Lastly, please state the word count: the number of words of main text (excluding words in the title page, abstract, reference list and any boxes or tables). Please see our example of a title page and follow the same layout.

Structured abstract

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 papers by reading only the abstract. Our estimate is that an initial decision is made on the abstract alone in 15-25% of papers. In a further 30-40% of papers editors look at the full paper for one or two specific points, which usually concern the paper's originality or methods. The remaining papers are read more fully before an initial decision is made. This is not as radical as it might sound: it is routine, for example, for conference panels to screen submissions by assessing abstracts. The 30-40% of papers that we send to external peer reviewers are read more fully by editors, and by reviewers and—if they survive external peer review—in painstaking detail by several people at our editorial advisory (or hanging) committees.

Screening research papers by reading abstracts.

Please note the general rules for abstracts in the LJPC:

• should be 250- 300 words long. (MEDLINE allows a maximum of 4096 characters and will truncate longer abstracts)
• 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

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 paper, substitute something sensible such as "population" as a heading instead of "participants" in an economics paper. Please do not simply delete the heading.

For standard original research papers please provide the following headings and information:

• 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, cross over trials, and before and after studies.
• main outcome measures - those planned in 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.
• conclusions – primary conclusions and their implications, suggesting areas for further research if appropriate. Do not go beyond the data in the paper. Conclusions are important because this is often the only part that readers look at.
• trial registration - registry and number (only for clinical trials)

Please note that confidence intervals should be written in the format (15 to 27) within parentheses, using the word "to" rather than a hyphen. For more details on writing structured abstracts please see Haines RB, Mulrow CD, Huth EJ, Altman DG, Gardner MJ. More informative abstracts revisited. Ann Intern Med 1990;113:69-76

Abstracts for meta-analyses and systematic reviews should have these headings:

• objective – what the review set out to determine
• design – type of meta-analysis, systematic review
• data sources - where included studies were retrieved from
• review methods - inclusion and exclusion criteria
• results - main findings with 95% confidence intervals
• conclusions - primary conclusions and their implications

Abstracts for qualitative research papers should follow the standard style but may need fewer headings:

• objective
• design
• participants
• setting
• results
• conclusions

Quality improvement reports also have their own style of structured abstract:

• problem
• design
• setting
• key measures for improvement
• strategies for change
• effects of change
• key messages and new information

Structured discussion

We encourage, but don't yet require, authors to write the discussion sections of original research papers in a structured way, to minimise the risk of careful explanation giving way to polemic. We suggest that the discussion follows this structure:

• 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

See The case for structuring the discussion of scientific papers

“What this paper adds” box

Please produce a box offering a thumbnail sketch of what your paper adds to the literature, for readers who would like an overview without reading the whole paper. 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 short sentences 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 short sentences 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.

Other items to include with your original research paper

• a word count for the main text (excluding the abstract, references, tables, boxes, or figures): you will be asked to enter this when you submit your manuscript online
• original data if you think they will help our reviewers or if we specifically request them
• copies of any non-standard questionnaires and assessment schedules used in the research
• copies of patient information sheets used to obtain informed consent
• copies of related papers you have published. This is particularly important where details of the study methods are published elsewhere
• copies of any previous reviewers' reports on this paper. We appreciate that authors may have tried other journals before sending their work to the LJPC. Please let us know how you have responded to previous reviewers' comments before submission
• names and contact details (including email addresses) of suitable peer reviewers; we usually choose who to send papers to but often find authors' suggestions helpful

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 LJPC
• a draft paragraph for This Week in the LJPC

To attract readers to the LJPC's original papers we publish short paragraphs giving an idea of the content and importance of each one. These paragraphs appear on a couple of pages at the front of the journal. Ideally, these are based on boxes of 90-100 words provided by authors. For this paragraph please provide:

• a short informative title - preferably a statement
• one or two sentences explaining the current state of the subject studied and where your paper fits in
• one or two sentence explaining the paper's relevance for non-specialist readers
• a brief summary of your study (including some key data to give readers a sense of the size of your study and its effects; but avoid repeating what has been said in the first sentence
• a sentence or two of conclusion and comment, perhaps looking to the future of the subject

We will use your draft paragraph as the basis for what we publish on the This Week page. This page is written by LJPC editors in a journalistic style. We will take responsibility for its content.

Short reports

These must not exceed 600 words with no more than one table or illustration and five references. Please provide a word count for the main text (excluding the references and the table or illustration).

The text of a short report has three parts

• introduction (untitled)
• participants, methods, and results
• comment

Short reports have no abstracts, so it can be hard for readers to discern from them the bottom line. To help readers, please give the main message of the paper in the first sentence of the comment section.

We would also like you to provide at the end of your short report’s manuscript a box explaining what the paper adds. Please see the advice section on papers for general advice on writing such boxes. Given that Short Reports are, by design, brief and usually have a single message, the box should need no more than two short sentences under "What is already known" and one under "What this paper adds" at www.londonjournalofprimarycare.org

Research pointers

We often hear that there isn't enough exciting science in the LJPC. We have become so concerned with high scientific standards and the need for a message of direct clinical or public health importance that we've squeezed out fascinating observations that don't have direct relevance. So we have introduced research pointers (please see Delivering drugs and making the LJPC less boring).

To be accepted as research pointers studies must be fascinating and not scientifically ridiculous. These articles have the same length and structure as short reports (up to 600 words with 5 references and one table or figure).

They should include a box with two subsections. The first should have, under a subheading What this paper suggests, a single short sentence summarising the paper’s main message. Under a second subheading What research is needed now, needs a single short sentence suggesting further work that could be done to gather more evidence.