Create an Edanz Account Today!

The 'write' order and IMRaD

Scientific enquiry can take a number of different forms. As a result, there are a variety of publication types, including papers describing original research, reviews, case studies, methodology papers, and theoretical papers.

By far the most common format for writing scientific papers describing original research is the IMRaD format. The letters in this acronym stand for introduction, methods, results and discussion, representing the sections lying between the abstract and references in such manuscripts (although in some journals, the methods section is presented at the end rather than after the introduction).

The International Committee of Medical Journal Editors (ICMJE), in their “Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Writing and Editing for Biomedical Publication.” section IV.A.1.a (General Principles), provide the following description of the IMRaD format and why it is used:

“The text of observational and experimental articles is usually (but not necessarily) divided into the following sections: Introduction, Methods, Results, and Discussion. This so-called “IMRAD” structure is not an arbitrary publication format but rather a direct reflection of the process of scientific discovery. Long articles may need subheadings within some sections (especially Results and Discussion) to clarify their content.”

The 'write' order

The following four sections describe the important components of each of these sections as well as some common mistakes to avoid. However, it is worth mentioning that these sections should not be written in the order in which they appear (or in which they are described here). Rather, there is a specific order in which the sections of a manuscript should be written to achieve maximum clarity and consistency throughout. The recommended order for writing these sections, with the addition of the abstract and title, is as follows:

  • Methods
  • Results
  • Introduction
  • Discussion
  • Title
  • Abstract

The methods can be written while you are performing the research or, for certain standard protocols, before it has even begun. Doing this early in the course of your research could make you aware of any potential problems in your study design, or point to additional controls you might not previously have considered. The advantage of this is that the methods can be adjusted before performing experiments, preventing the need for time-consuming and costly repeats of experiments already performed.

With the methods written up and the experiments performed, you will want to analyze your results to determine how they relate to your hypothesis and what they actually show. It is pointless writing the introduction prior to this stage because the results you obtain will determine how the paper needs to be ‘framed,’ that is, what context the results are described in. Therefore, the results should be analyzed and written up second. During this stage you will determine how your data should be presented (for example, in tables, graphs, schematics or photographs; see tip on graphics), how they need to be analyzed (see tip on statistics), and what they mean. Once decided, you will then need to describe them.

By now you will have a good idea of how your findings relate to your hypothesis and the existing literature in your field. It might be necessary at this point to ask a different research question or to change the focus of your research. Following such a change, re-analyses of your data and/or additional experiments might be necessary to make a complete story. Once these are done, the introduction can be written, to provide the context, and then the discussion can be written to describe the relevance of your findings within that context. Finally, with all of that fresh in your head, the abstract and title, the important components of which are described in previous tips, should be written last.

Setting the scene

The introduction must provide the reader with sufficient background information for them to put your work into context. It needn’t and shouldn’t be a comprehensive literature review of the field: that is what review articles are for. Instead, it should present “the problem,” basically whatever the research question is, thereby defining the rationale for the study. The introduction should also briefly explain how you addressed this problem and what was achieved. Put another way, it should be clear from the introduction what related work has been done before, why the current study was performed, what you did, and what you found.

Literature review

A comprehensive literature search should have been performed before launching into your study. If not, you run the risk that someone has previously done what you intend to do. However, it is also possible that similar or related studies are published during the several months it takes to perform the research. Therefore, the literature should be reviewed on an on-going basis to ensure that you are up to date with all developments in your field of research. As with all references to the literature, the literature cited in the introduction needs to be current, balanced and relevant.

What this means is that:

  • You should not cite papers that don’t directly pertain to the research you plan to describe
  • You must cite all relevant papers, not only your own research and papers that support your hypothesis, but also papers that contradict your findings or propose alternative ideas
  • Only the most recent papers showing a particular finding should be cited, unless referring to an older paper to explain the evolution of thought in the field or the development of a particular method

The minimum amount of background for a reader to understand the rationale for your study is all that is required. If a reader wants to know more they will find a review on the subject; indeed, many authors refer readers to review articles for additional information, thereby reducing the length of their introduction.

It is usually a good idea to briefly describe what was done and what was found at the end of the introduction, but it is important not to go into too much detail or you will end up repeating what is already described in the methods and results sections. A sentence or two for each is usually sufficient.


Finally, any non-standard abbreviations, technical terms and terms that might be unfamiliar to some readers should be clearly defined in the introduction. For example, in a paper describing research on Leishmania major, it would not be helpful (or appreciated by the reader) if it was left until the discussion to mention that this is a protozoan parasite responsible for the skin disease leishmaniasis. Similarly, in a paper describing findings relating to the protein BCL-10, the fact that it has been shown to induce apoptosis and activate the signaling molecule NF-κB should be mentioned in the introduction rather than being left until the discussion.


Sample of Introduction

In the example above, published in The Journal of Clinical Investigation (doi:10.1172/JCT38289; reproduced with permission), the authors clearly state what the problem is and follow this with five paragraphs of background (not shown) explaining the results of previous work and their implications. This leads nicely to the rationale for the study, which is logically followed by a description of what was done in the present study. The authors of this paper chose not to mention their findings in the introduction, possibly because the description of what was done was quite detailed, but most likely because the results section immediately follows the introduction in JCI papers, with the Methods coming after the Discussion section.


  • Minimum amount of background required to understand “the problem”/hypotheses
  • Clearly framed “problem”/hypotheses
  • Balanced and current literature cited
  • Technical and non-familiar terms clearly defined
  • Brief description of what was done and what was achieved in the final paragraph

What you did

The methods section of your manuscript should contain sufficient information for a capable researcher to accurately repeat the experiments you describe. If essential information is left out, the exact conditions might not be replicated, leading to different results, potential misunderstandings, or worse, accusations of falsification. Thus, the methods section needs to be comprehensive.


The methods section should be written in the past tense. For example, “sections were stained with…” and “data were analyzed using…” An exception to this is references to tables or figures in the manuscript, for example “The patients’ clinical characteristics are listed in Table 1.”

Another exception is when providing a definition or describing the current consensus on something. For example, “the cells were subjected to hypoxia, which induces HIF-1 expression…” Here, although what was done is described in the past tense, the fact that hypoxia induces HIF-1 is described in the present tense because it is a general phenomenon not limited to the present paper.


The suppliers of all reagents and the manufacturers of all equipment used should be listed. Some journals also request that the locations, that is, city, state (if in the USA) and country, of these companies are provided. When talking about equipment, kits, or reagents, you should use familiar terms to define the particular item you are describing, rather than just a manufacturer-specific term or model number.

For example, rather than writing “Absorbance in each well was measured at a wavelength of 492 nm using a Beckman Coulter AD 340C,” which would be meaningless to the majority of readers, you should write “Absorbance in each well was measured at a wavelength of 492 nm using a multi-well plate reader (AD 340C, Beckman Coulter)” or perhaps “Absorbance in each well was measured at a wavelength of 492 nm using an AD 340C multi-well plate reader (Beckman Coulter Inc, Fullerton, CA, USA)”.

Other information

Methods should only be included if the results of the described experiments are provided. If an experiment you performed didn’t work, or didn’t provide the results you needed, and you have opted to leave the results out of your paper, then there is no need to describe the associated methods.

Use appropriate subheadings to separate materials and methods with different purposes. If available, use a Supplementary Methods section to provide detailed information so that the printed methods section can be kept brief. Novel techniques need to be described in detail so that they can easily be replicated, but established and commonly used techniques can be referenced as long as any variations between the method used in the present study and that described in the cited study are clearly described. Above all, be precise and ensure that all units are correct and all conditions (such as times and temperatures) are clear.

Finally, if any statistical analysis was performed to assess the significance of your data, describe the statistical methods used, including the threshold(s) selected for significance, at the end of the methods section.


The sentence “…homogenates were spun at 10,000 × g and 4 °C for 12 min” includes the important details of time and temperature that would have been missing if the author simply wrote “…homogenates were spun at 10,000 × g”, or even more simply “homogenates were centrifuged.” These details could have been essential to obtaining the result you did, and so should be explained.

Similarly, rather than saying “Then, 10 μl of a propidium iodide solution was added to the cells,” which is meaningless unless the reader knows the concentration of the propidium iodide solution, you should write “Propidium iodide was added to the wells to a final concentration of 0.5 μg/ml.”

The figure below, showing a couple of excerpts from the methods section of paper published in The Journal of Clinical Investigation (doi:10.1172/JCI37155; reproduced with permission), indicates the important components of a methods section and how these fit together.

Sample of Methods


  • Clear subheadings for methods/materials with different purposes, with materials described first
  • Methods described in past tense
  • Novel methods described in full detail, sufficient for a capable researcher to reproduce
  • Established methods referenced to previous literature
  • Suppliers/manufacturers provided, including locations if requested
  • Statistical methods described

What you found

The results section is possibly the most important section in your paper. In this section you will describe the main findings of your research, which is what everyone who is going to read your paper wants to know about. Also, whatever findings you obtained will determine how the introduction and discussion sections are framed, what target journals you can consider, and what direction(s) your subsequent research needs to take.

Look at the data
The easiest way to approach writing a results section is to consider all of your findings and what they mean or suggest. You will already have analyzed your data and probably also generated a number of figures and/or tables to show it in a clear and concise manner.

Later tips in this series describe some important considerations to keep in mind when preparing display items and performing statistical analyses, so I won’t go into much detail on those processes here. However, it is important to remember that graphics are important components of the results section, and therefore, that there should be no redundancies or duplications among the text, figures and tables. Put simply, if something can be more clearly shown in a figure or table than explained in the text, then use a graphic and refer to it briefly in the text; if something can be easily summarized with text, then there is no need for an additional graphic showing the same thing.

Tell your story

Once you have a clear idea of what results you want to include and what each of them shows, you should assemble them in a logical order to make a ‘story.’ You will have already described your hypothesis or research question(s) in the introduction; use the results section to lay out all of the evidence you have gathered, building up a solid case to support your hypothesis or to exclude alternative explanations. Each different finding should have its own subsection, beginning with a subheading in the present tense. These subheadings should match those in the methods section and the headings used in figure/table legends.

The results themselves should be described in the past tense, like the methods. The more types of evidence you can provide for a given hypothesis (and the less ambiguous these are), the more irrefutable your conclusions can be. Resist the urge to discuss the implications of findings or go into detail about what they mean—that is what the discussion section is for. Rather, present the evidence and let the reader draw their own conclusions.

Make comparisons
Results sections frequently involve comparisons between a test sample and a control, or between before and after time-points, so you should be aware of some common errors made when describing comparative results. For example¸ the sentence “Expression levels of p53 in smokers were compared with non-smokers” should actually be “Expression levels of p53 in smokers were compared with those in non-smokers.” The critical point here is the placement of “were compared” (or in other situations, “compared with”): if the comparing term appears between the words describing the two items being compared (here, p53 levels in smokers and p53 levels in non-smokers), then enough information needs to be provided either side of the comparative term to make it absolutely clear what is being compared. An alternative to this is to place the comparative term before or after the words describing the items being compared: for example, “Expression levels of p53 in smokers and non-smokers were compared.”

While still on the subject of comparisons, it is important to remember that relative terms, such as “more,” “higher” and “faster,” require an accompanying “than” clause to explain what this change is relative to. For example, in the sentence “transgenic mice showed higher levels of cortisol” it is unclear what these levels were higher than; thus, a “than clause,” such as “than control mice,” is required.


The figure below, showing a couple of excerpts from the results section of paper published in The Journal of Clinical Investigation (doi:10.1172/JCI37155; reproduced with permission), shows some of the important components of a results section.


  • Use figures and tables to summarize data except where such data can be easily summarized in the text
  • Describe results in the past tense
  • Compare like with like
  • Do not duplicate data among figures, tables and text
  • Show the results of statistical analyses, for example, p values, in the text.

What does it all mean?

The discussion section of your manuscript is critically important. It is where you pull together all the ‘threads’ of evidence you have presented in the results in the context of the background you presented in the introduction.

Unfortunately, many authors, particularly those from non-English-speaking countries, overlook the importance of this section considering it sufficient to merely present their results and allow the reader to draw their own conclusions. However, presenting your results without describing their implications leaves them open to interpretation and reduces the impact they could have. Journal editors want papers that will advance the field and generate an impact. Therefore, use the discussion wisely to maximize the impact of your findings.


A good discussion will begin by restating the study question and any hypotheses presented in the introduction. This should be followed by a summary of the major findings of your study so that it is immediately clear how you have advanced the field. Start with the most important or relevant finding and then move to progressively less important ones. However, do not yet discuss results that are perhaps controversial or difficult to explain. At this stage you only want to describe the major findings that directly answer the research question you set out in the introduction and/or those that directly relate to your hypotheses.

Avoid making grand statements that are not supported by your data and/or overstating the importance of your findings. The word “suggests” is preferable to “shows,” and the word “proves” should never be used. Also, there should be minimal repetition with the results section, with only brief descriptions of the main findings required before launching into their implications. A mixture of tenses is required, with the past tense used to describe individual results and the results of previous studies, and the present tense used to describe their implications.

Put it in context
The next part is the component of a discussion that is often overlooked and a frequent cause of rejection from journals. Having reiterated your initial question and major findings, you need to describe their relevance and significance. This is where you put your findings into the context of previously published literature and discuss their implications. This part forms the bulk of the discussion section, showing the reader (and importantly, the journal editor) what your findings actually mean in the light of the existing literature and how they relate to the efforts of others.

All possible alternative interpretations of your study should be described and excluded (or at least shown to be unlikely) wherever possible. If alternative interpretations remain viable, the study is considered ‘incomplete,’ or at least ongoing, and experiments to rule out the alternatives or determine which of the alternatives is correct should be described at the end of the discussion section as future research.

Once the major findings have been put into context, any controversial or difficult to explain findings should be mentioned along with plausible explanations for them. It is perfectly OK to speculate here (but not too wildly), but it is absolutely essential that these findings, and any inconsistencies, are discussed and addressed rather than ignored. No new results or terms should be introduced in the discussion section; all findings should be described in the results section and relevant terms will all have been introduced in the introduction section.

Finally, any limitations of the current study should be explained. Peer reviewers are likely to comment on such limitations anyway, so it is best to be ‘up front’ about them and state what they were; doing so might even improve your chances of a positive peer review and thereby shorten the time to publication. The fact that your study has certain limitations is not a problem in itself, and most studies have limitations of some sort. It is therefore important to acknowledge these and describe how they can be addressed in future research. For this reason, the description of limitations is usually followed by a description of future research.

Some journals have a separate conclusions section, but even in those that don’t, the same content should be merged with the discussion and contained in the last paragraph. This final section/paragraph should briefly restate the key findings and their significance, describing how your study represents an advance in the field, but avoiding direct repetition. The novelty and significance of these findings should be mentioned, but again, it is important not to over-emphasize either of these. Future studies should be mentioned where relevant, and can be the subject of the final sentence if the current study is preliminary. If your study is not preliminary, end with a strong statement that summarizes the impact of the study without over-stating its importance.


The figure below, showing excerpts from the discussion section of paper published in The Journal of Clinical Investigation (doi:10.1172/JCI37622; reproduced with permission), shows some of the important components of a discussion section and the concluding paragraph at the end.

Example of Discussion


  • Start by restating the problem/research question and then state the main findings of your study
  • Describe results in the past tense, but implications in the present tense
  • Put findings in the context of the existing literature to describe their implications
  • Describe the implications of all results obtained; do not ignore ‘inconvenient’ ones
  • Avoid repetition, introducing new terms or results, and making grand statements about the importance of your findings
  • Describe the limitations of your study and future directions for research in the field
  • End with a strong statement describing the relevance and significance of your study