What you need to know about this (admittedly not most exciting) section of a research paper – beyond the basic advice.
Materials & Methods sections, which I will call M&M sections in this post, may not be the ones that are the most exciting to write. (But hey, they are probably the easiest ones). Nevertheless, the sections that describe how you actually performed your experiments or simulations are still really important.
I know you are at a stage in your scientific career where you know how to write a decent Materials and Methods section. Let me show you how you can write an excellent one!
This blog post assumes that you know that you should include details about manufacturers and models of the tools you have been using, use SI units and write this section in the past tense. Here are instead five things you need to know beyond basic and field-specific advice:
1. Provide the right amount of detail
You’ll often read that you should provide as much detail in your Methods section that readers will be able to replicate your results. And that’s true – to some extent. Not many of your readers will actually attempt to reproduce your findings. This means that most readers will read your M&M section with a different intent: They want to understand whether the approach you used is suitable to solve the problem you identified and whether you performed the chosen methods correctly.
Take a moment and reflect on what your approach to reading M&M sections in other people’s papers is. I would guess that you often skim read those paragraphs to understand, for example, whether the authors used the right parameter X for method Y. Or you might go to the M&M section to understand the logic of their experimental setup. Am I right?
Because most readers won’t actually try to perform the exact same experiments you report on, I believe, writing an incredibly detailed M&M section isn’t the way to go. I rather recommend attempting to reach both types of readers, the ones trying to replicate your results and the ones assessing how trustworthy your results are. How do you do that? I recommend writing all descriptions in the M&M that is included in the main part of the paper for the latter readers. Additional detail, such as experiments you performed to optimise your measurements, can be provided in the Supplementary Information (see also Tip #4 on this point).
If you are unsure how much detail you should include in your M&M section, read some papers in your field to get a feel for it. There are often some unspoken common practices regarding the information that needs to be included.
2. Use a storytelling structure
Implementing a storytelling structure in your paper is essential. If you tell a story instead of just putting a list of findings in front of your readers, you make them understand the context and importance of your study, you make them care. But using story elements doesn’t exclude the M&M section. There’s one story element in particular, that is essential in the methods section: purpose. This lets readers know why you performed a certain measurement. For example, I recommend writing:
To compare the elemental composition of our samples, we performed X-ray diffraction (Manufacturer, Model) on the samples with 1, 3 and 5 wt.% Cu.
instead of:
X-ray diffraction (Manufacturer, Model) was performed on the samples with 1, 3 and 5 wt.% Cu.
You may think it’s self-evident why you performed these measurement but trust me when I say, as someone who reads and edits a lot of people’s papers, that for the reader it often isn’t. Including these simple statements of purpose helps the reader tremendously to connect your methodological descriptions and your results.
3. Structure the M&M section in the same way as your results section
I sometimes see manuscripts where the authors have put a lot of effort into structuring their results section, while the methods section is basically just one long paragraph. I think the M&M section deserves a little bit more attention, not least because your peer-reviewers are going to use it to assess whether your manuscript is fit for publication.
So, let’s make their job and your other readers’ lives easier and arrange the descriptions of your methods to match the structure of your Results section. This includes ordering the information in the same way as in the Results section. And if your M&M section is rather long, I recommend dividing the text into subsections (just as you did in your Results section).
4. Organise your Supporting Information and refer to it
If you choose to include additional methodological detail in the SI, make some effort to structure the SI as well, even though there often aren’t any instructions by the journal. And when you refer to the SI in the main text, clearly indicate where the additional information can be found. For example: “Additional detail on the electrochemical experiments can be found in section 3.1. in the Supporting Information.” There shouldn’t be any information in the SI, that hasn’t been referred to in the main text.
5. Don’t self-plagiarise
I know it’s annoying. When you have been using a certain method for a while and described it in previous papers, it can be hard to find a novel and concise way to write about it again. Still, copying and pasting sentences that have been previously published is considered plagiarism – even if they are your own words. However, there are degrees of what is also called “text-recycling”. And there continues to be discussion among editors as to whether a certain degree of text-recycling should be allowed, for example for using a standard description to describe a collaboration or an experimental setup.
Nevertheless, plagiarism detection software that most journals use will likely find any sentences or paragraphs in your submitted articles that you have “recycled” from a previously published study. Editors at BioMedCentral write in their text-recycling guidelines published on the website of the Committee on Publication Ethics (COPE) that journal editors should use their own judgement when deciding whether the overlap is acceptable. They recommend that editors take into consideration whether the authors have indicated that a method has been described elsewhere in detail and provided a reference.
To sum up, unless the journal has indicated that recycling methods descriptions is okay, don’t do it. So, what can you do instead? The first thing to consider is whether you need to reiterate the method descriptions at all. If the main message of your paper isn’t about the method in question, it may be enough to cite a previous publication. If you think a description of the method is necessary for the readers to follow the rationale of your paper, there may be a way of using a different angle to describe it or highlighting a different detail. If there aren’t any elegant solutions, you may simply need to harness the flexibility of the English language and rewrite the sentences even if you lose conciseness.
There you have it: 5 advanced tips for writing better Materials and Methods sections. Are you planning to implement any of the tips when writing your next paper? Please leave a comment below!
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