5 Things you need to know about writing good paragraphs in scientific papers and grant proposals

Learn how long a paragraph should ideally be, which the most important sentences are and how to use paragraphs to achieve flow in your manuscript.

Creating a well-written manuscript goes beyond being proficient in English. There’s a little more you need to know about scientific writing. Once you have understood how to communicate your research as a story and know what language mistakes to avoid, it is crucial to dive a little deeper into how to best structure a paper or grant proposal. In any manuscript, the important structural unit is the paragraph. Here are 5 important things about paragraphs you should be aware of before you start writing.   


1.  One main message

I talk a lot about how important single main messages are in papers and grant proposals, the same holds true for their building blocks – the paragraphs. A paragraph should make sense on its own and have a clear message. If you are not able to summarise the content of a paragraph you’ve written with a few keywords or in one simple sentence, the main message of your paragraph is unclear. This can be because you are covering two or more topics too different from each other to be covered in one paragraph, or because you need to add some information on how the topics are connected.


2. The ideal length

The most common problem with paragraphs I see in scientific writing is that they are too long. Often this is because authors are covering more than one topic (see point 1). The problem with long paragraphs is that they are harder to read, especially if the author meanders through several different topics without the main message being clear. Don’t be afraid of short and concise paragraphs! A length of 100-200 words is optimal. If your paragraphs tend to be longer, I suggest analysing them to see how you could divide them up sensibly.


3.  The first and last sentences

The first and last sentences of a paragraph are strong positions. Even when people skim-read your paper or proposal, they tend to pay a little more attention at the beginning and the end of structural units such as paragraphs and sections. In fact, I often catch myself only reading the first sentences of paragraphs in order to decide whether it’s worth reading the whole paragraph or to skip to the next one. Therefore, it is wise to make use of the first and last positions in a paragraph.

In the first sentence, it is crucial to signal to the reader what the paragraph will be about. One way to do this is to provide a topic sentence, which summarises the content of the paragraph. An example of for this is the following sentence:

There are a number of clear advantages in extending the spectral range of SPAD detectors into the short-wave infrared region […].” Firstly, compatibility with the optical fibre low-loss telecommunications windows is a fundamental advantage in many fibre-based applications. Secondly, [….] Thirdly, […] Finally, operation in the SWIR will mean enhanced atmospheric transmission, especially through obscurants such as smoke, smog, fog and haze.
— P. Vines et al.

Here, the first sentence states that there are many advantages for modifying a certain model system and in the rest of the paragraph these advantages are listed.

In some parts of your paper it might make sense to describe the idea or purpose behind an experiment or a hypothesis in the first sentence. You would then outline the methodology and results of the experiment in the middle part and finish the paragraph with the conclusion of the experiment. Here are two examples:

The subjects learned stimulus-outcome relationships that required the formation of conjunctive representations. Our task was based on [...] The task stimuli consisted of [...] We used [...]. AB and C predicted the target 70% of the time and B and AC predicted the target 30% of the time. [...] Optimal performance required learning the value of stimuli as distinct conjunctions of features (i.e., conjunctive representations).
— I. C. Ballard et al.
To assess the possible impact on Bmp signalling, we analysed phospho-Smad159 (p-Smad159) localisation. [...] Thus, higher levels of p-Smad159 cannot simply be explained due to increased expression of Bmp ligands.
— A. Senft et al.

The first sentence of the first of the above examples describes the rationale of the experiment, in the second example the authors clearly state purpose and methodology of their experiment in the first sentence. In both examples, the last sentence presents the conclusion of the experiment.

In other cases, better flow and readability is achieved by stating the conclusion in the first sentence, see this paragraph for example:

The measured DCR demonstrates a vast improvement when compared to previous Ge-on-Si work. Warburton et al. reported [...] There is a similar relationship when our results are compared to results from Martinez et al., who reported [...] This considerable reduction in DCR has resulted from [...] In order to fully ascertain the relative contributions to DCR, we are initiating a series of measurements on samples with different diameters and Ge thicknesses.
— Vines et al.

In the rest of the paragraph, the authors go into detail about the evidence supporting this conclusion and offer interpretations. The paragraph finishes with an outlook of further experiments.

4.  Flow

Creating paragraphs that communicate a single main theme with a good beginning and end isn’t enough. The paragraphs also need to be connected with each other. Otherwise you’ve merely perfected completely distinct units. In order to make your manuscript easy to read, you need to create flow. This means that your reader will be easily able to go from one idea to the next without wondering what one thing has to do with the other. On a paragraph level, you can achieve this, for example, by relating back to previously communicated information in the first sentence of a paragraph. Similarly, you can use the last sentence of a paragraph as a bridge to link to the next paragraph.


5.  Planning

And one last tip: You’ll be writing your manuscript more efficiently, if you plan out all paragraphs before you write your paper or grant proposal. Even though you might realise when writing that you need to make some changes, it’ll give you a useful outline that you only need to fill with more details. By planning your paragraphs beforehand, it’ll be much easier to write a concise story that flows well.

I’d love working with you to get the story right in your manuscript or proposal. Just send me a quick message or check out the different coaching and editing packages I offer.

Referenced studies

Vines et al., Nature Communications 10, 1086 (2019).

Ballard et al., Nature Communications 10, 1073 (2019).

Senft et al., Nature Communications 10, 1089 (2019).

About the Author

I’m Dr. Anna Clemens, a scientific editor and writing coach for scientists. I give workshops about scientific writing, offer strategy calls and edit papers and proposals. I’d love to work with you, please click here for more information.

I also regularly blog about scientific writing and write articles about science for magazines and websites. I hold a PhD in Chemistry/Materials Science.

When I’m not at my desk, I’m probably out and about with my dog and assistant Zuza.

I’d love to connect on Twitter (@scientistswrite) and Instagram (@scientistswhowrite)