For the previous episode in this series on how to write a scientific paper, see here.
Time to start writing up the results! Before you go on, have a look at the earlier post on figures, as it tells how to develop the storyline for this section.
How to write the Results section of a scientific paper? If you have followed the approach in the post on figures, you have now in practice chosen your order of presentation. You have categorized your results (and figures) into Setup, Confrontation, Resolution, and Epilogue. Or, if the movie script analogy is starting to annoy you, into categories that serve a similar purpose.
Results of the first category pave way for what follows. They introduce the reader to your data; they make your final conclusions credible by showing what is in your data and letting the reader gauge whether it looks OK. Results of the second category show that there is an open scientific problem, that there is something surprising that needs to be sorted out. Results in the third category present the Resolution, the key finding that solves the problem (or opens doors to even more problems). Results of the last category, Epilogue, are there to show what follows from the main result and why the main result is important. They would not necessarily work as stand-alone results.
This will also be the order in which your results will be presented.
Please note that the above arc is not necessarily historically accurate (it almost never is): the aim is not to present your scientific findings in the order they came to be, but to present a compelling argument and to provide a bit of entertainment on the way in the form of a good story. And remember what we discussed already in Part I: the paper should only include those results that serve the story and play a role in one of these categories. The rest should be left aside for future papers (or for the Supplementary Information document).
This is the overall arc of the Results section, or, if you are writing a letter-format paper, the arc of the bulk of the paper, sandwiched between the introduction and the conclusion. Make it sure that the reader can easily follow the arc. She should always know where she is and where she should head next.
One way of making sure that the reader is always on the map is to use informative subsection headings. This may require you to divide the four categories into further subsections. A great way of developing subsection headings is to compress each result into a single short sentence and use this sentence as the heading. This way each result gets its own subsection where it can be explained in detail. Note that here, “result” does not necessarily mean a single plot or figure, but rather a conclusion that may be based on several pieces of evidence.
If the results section is organized like this, the reader can get a quick overview of the whole section by just scanning the subsection headings; remember that most of the readers just skim. These skimmers include the editor who decides whether to desk-reject you paper or to send it out to referees.
The above technique is an example of so-called signposting, where the whole paper is made more accessible by covering it with signposts that tell the reader where she is. Clear section headings help, and so do clear figure captions, whose first sentence should tell what the figure is about. Clearly formulated key phrases are also very useful. As an example, it is good to have in the Introduction a sentence that begins with “in this paper, we show”. It is also good to begin each paragraph with a topic sentence that tells what the paragraph is about.
For the results section, the most important signposts are the section headers, the first sentences of figure captions, and something we haven’t discussed yet: the first sentences of all results subsections. The first sentence of each subsection should provide motivation and background: why was the analysis done that led to this result? Why are we discussing this result? This sentence should begin with “to understand why X, we measured Y…” or similar. Even if the motivation has been mentioned in the introduction, the reader should be reminded of it, unless the paper is a very short letter and the introduction is just a few paragraphs away.
So what else is there in a results subsection? Well, results, of course – but there are several layers here. First, the lowest layer contains your “pure” results. Those are, in a way, just data: you have measured X, here’s what you got. You have computed Y, here is a table. The second layer contains direct and unambiguous interpretations of these data: the distribution of X measured under condition A clearly has a lower mean than when measured under condition B. Y grows faster as a function of time than Z. And so on. While such statements may already contain the main conclusion, a third layer of interpretation is usually required – that of giving meaning to the findings, of asking (or telling) what the results mean, of presenting new hypotheses. How do the results bring you closer to answering the broad problem that your paper addresses?
The above layers form a logical order of presentation for each of your results subsection. Begin the subsection with motivation and background. Then briefly tell the reader what you have done, either referring the reader to the Methods section or, if you are writing mixed results and methods, presenting your methods here. Then explain the results that you have obtained and talk about how your interpret them. Make it clear to the reader what layer you are talking about: what is indisputable fact, what is interpretation, and what is speculation. Use signposts for this—saying “these results can be interpreted as follows” and continuing with interpretation helps the reader to understand there might be other ways of interpreting the results. Do not exaggerate or overgeneralise: if there are limitations that haven’t been addressed already (say, in the Methods section), be open about them.
There are traditions in some disciplines where the Results section is strictly about results, and in the fundamentalist interpretation, this would mean only including the first layer (pure data) and perhaps some of the second layer (“these data have a lower mean than those data”). Then, the meaning and interpretation of the results would only be discussed in the Discussion section and not even mentioned in the results. To me, this is, well, insane. It must have been invented by the same evil people who run journals that send papers to referees where figures are separated from the text and the captions are separated from the figures. Why, oh why, should one make the reader’s life so difficult that she has to jump back and forth between Results and Discussion? I cannot think of any other explanation than purely evil intent. But if you work in one of those disciplines and have to publish in journals that demand this, then well, I guess you have to obey the rules. Or to look like you obey the roles. But don’t do it willingly: always try to sneak in at least one sentence that explains your findings. Rejoice if you get it through the editor and the referees!
Before we move on to discussing the Discussion section, one more trick. This has to do with understanding how the mind of the reader works; we’ll talk more about that later. It is very common to begin a paragraph in the results section with “In Figure X, we see that…” Now, next time you read a paper, try to be conscious of your own response to this. What do you do? Do you directly jump to Figure X to have a look, and then try to get back to the middle of the sentence that you were just reading? No? Can… you… resist the impulse? Noooo! OK, but you still feel the impulse, don’t you? It is impossible not to feel it! And the impulse makes it harder for you to follow the sentence to its conclusion. So always refer the reader to the figure last, not first: finish the sentence with “as we see in Figure X” or similar. This way, when the reader arrives at your mental hyperlink, she has already read your sentence and knows what to look for in Figure X.
Next, we’ll discuss the Discussion section.
[Finally: the book. Many have asked me to write a book based on these posts. I’m working on it in an on-and-off way whenever there is time. Having three small kids and being the vice head of a large department doesn’t exactly help. I’ll be happy if the book is out in 2018. My plan is to self-publish, first on Kindle Store and then as an on-demand print version (it is nowadays easy to sell printed-on-demand books through Amazon and other online stores at very reasonable prices; the technology is there). I am at the time being not even considering traditional publishers because i) they would slap a high price tag on the book, limiting the number of readers, and ii) they would then take 85%-90% of said high price without doing much else. I don’t see this as reasonable because, with modern tools, publishers can simply be circumvented. Sorry to say, but traditional publishers: for books like this, you are no longer needed… PS Does anyone know a reasonably-priced proofreader?]
[Update: it’s out as of 1st of November 2018, see below!]