How to write a Methods section in your research paper
The Methods section is the part of a scientific paper that describes how the study was carried out. This section describes each technique that was used in the study and any relevant details about the materials, subjects, and so on. Some journals refer to this as the ‘Materials and Methods’ section, and some clinically-focused journals will refer to it as the ‘Patients and Characteristics’ section.
The primary aim of the Methods section is to describe how the study was performed in enough detail that another researcher could replicate it exactly if they wished to. It is always written in the past tense (e.g., ‘1 mL of solution was added to each sample’), and can be the easiest section of the paper to write; many researchers start with this section first when writing a paper.
How should the Methods section be organised?
A Methods section is divided into a number of subsections, each of which is dedicated to a single technique or collection of related techniques. The heading of each subsection should either clearly state the technique that subsection describes, if it only describes one, or the aim of the set of techniques, if the subsection describes multiple related techniques. For example, a subsection that only explains how qRT-PCR was carried out could simply be titled ‘qRT-PCR’, whereas a subsection describing complete blood count, enzyme tests, and cholesterol panel could be titled ‘Blood testing’.
Within each subsection, the information should be presented in order from the most general to the most specific. For example, in a study using human subjects, the entire study population should be described first (e.g. ‘Subjects were an average of 40 years old (range: 35–45), and 50% were male (23/46).’), followed by more detailed descriptions of each of the experimental or control groups within that population (e.g., ‘The subjects in group A smoked 1–2 times per week, the subjects in group B smoked 2–10 times per week, and the subjects in group C did not smoke.’).
Information within subsections should also ideally be presented in chronological order. For example, patient recruitment should be described before explaining how the recruited patients were divided into groups A, B, and C.
The subsections themselves should be presented in the same order in which the techniques that they describe are mentioned in the Results section. For example, if Figure 1 shows immunofluorescence microscopy images of cultured cells, the subsection describing the cell line and culture conditions, as well as the subsection describing how the microscopy was performed, should appear early on in the Methods section. Using this approach will help readers quickly and easily find the detailed information pertaining to each experiment as they read through the paper. The exception to this rule is ethics/consent statements and descriptions of statistical analyses, as discussed in more detail below.
What information should be included in the Methods section?
In addition to describing how each experiment was performed, the Methods section should provide detailed descriptions of all of the materials and equipment used to carry out those experiments. Generally speaking, most journals require that the supplier name and location (city and country) be specified for any specialized reagents and equipment mentioned in the Methods. It can also be helpful to provide catalogue numbers for highly specific materials, such as antibodies. As mentioned above, the ultimate goal is to provide enough detail to enable another researcher to reproduce each experiment exactly, so it helps to be as specific as possible.
In the case of studies involving experimental animals, an ethics statement should be included that clearly states whether ethical approval was obtained to perform the study and that cites the name of the ethics board that provided this approval. For studies involving human subjects, a similar ethics statement should be included, as well as a statement of whether the subjects consented to participate, and what type of consent this was (e.g., written or verbal, informed or otherwise).
Any statistical analyses performed as part of the study are typically described in the final subsection of the Methods. When writing this subsection, be sure to clearly reference the technique(s) described earlier in the section that each statistical test was applied to. For example, instead of saying: ‘Data were analysed by Student’s t-test.’, specify which data you are referring to: ‘The average values for group A and group B were compared by Student’s t-test.’
Some specialized types of studies need to comply with formal guidelines for reporting of methods (and other aspects of the study), so check carefully to see whether this applies to your situation. For example, papers reporting the results from randomised controlled trials should conform to CONSORT guidelines, and systematic reviews and analyses should comply with PRISMA guidelines for reporting. We recommend consulting any such relevant guidelines when writing the Methods section, and checking with your target journal to see whether any related documents such as checklists and/or flowcharts should be included in the Methods or as a supplemental file when the paper is submitted.
On a related note, some journals have specific requirements for Methods reporting, for example using the. STAR guidelines (Structured, Transparent, Accessible Reporting). It’s helpful to check the publisher website of your target journal as it may offer downloadable guidance for how to apply these standards to papers prior to submission.
How to reduce the word count of the Methods section
Given the extensive amount of information that needs to be presented in a Methods section, this part of the paper can sometimes become very lengthy and exceed your target journal’s word limit. Fortunately, there are a number of ways in which the word count can be reduced without omitting any crucial information.
For established or commonly used methods, it is appropriate to cite an article or other resource that describes that method in detail instead of providing a lengthy description in your own paper. For example: ‘Cells were harvested and sorted as described by Chen, et al. .’ If you used a previously published technique but modified it slightly to adapt it to your study, this same approach can be used; for example: ‘Western blotting was performed as described by Fouquet, et al. , with minor modifications, as follows: …’.
Another useful approach for decreasing the word count of the Methods section is to reference the supplier’s protocol for kits or any other reagents that come with specific instructions for use. For example: ‘Total protein was isolated using the Gerard Protein Extraction Kit (Gerard Bio, Inc., London, UK) according to the manufacturer’s instructions.’
Finally, tables can be used to present detailed information that may be too extensive to include the Methods or too difficult to interpret when incorporated into the text, such as lists of primers and their sequences, or lists of antibodies and their dilutions. While including this type of table in the main body of the text could distract readers from the study findings, many journals permit the inclusion of tables that support the methods in the Supplementary Information, so that the information is available if readers wish to seek it out, but does not interrupt the flow of the text.
If you are seeking additional support for writing or revising your Methods section, we are here to help. Charlesworth Author Services provide expert English language editing and publication support services. Why not get in touch with a member of our Charlesworth Author Services team for more information.
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