How To Write Scientifically

Believe it or not, but scientific writing is storytelling. Of course, we do not tell fictional stories, but stories, nonetheless. If we did not tell a story, we could simply publish our methods and results section. Instead, we add an introduction to frame our research question, and a discussion to interpret our findings. Altogether, our reports and articles should form a coherent story, including characters (e.g. our study organisms, concepts, molecules or ecosystems), a plot (why are we performing this study and how do we plan on finding an answer to our research question?) and a resolution (research findings and interpretation). By telling our story, rather than simply presenting our data, we engage the reader and can point to the main message and implications of our findings.

To tell this story in the best way possible, you must structure your content in a logical way and include only what is relevant to tell that story. NB! That being said, you should not exclude data or results just because they do not support your hypothesis. This, and cherry picking of results, is unethical!

Techniques to brainstorm and organize your ideas

There are several techniques you can use when trying to find the structure of your text. Here we have listed some that have been included in the book "The Scientist's Guide to Writing" by Stephen B. Heard. You can use all of them in the order we have provided, or just some of them – find the method that works best for you.

When creating word stacks you can let go of your worry of unfinished ideas, bad transitions and structure in general. All you have to do is to create an unsorted list of points you want to include in your text. There does not have to be any hierarchical structure or order, and you can note down question marks behind points you are uncertain about. Write down what comes to your mind - seeing your ideas on paper might help generate new ones.


A general outline is basically a structured word stack or a linearized concept map. Here you list your ideas in the logical order you want them to appear in the text.

Many struggle to put the first sentence down on the paper as if it must be perfect from the first letter. This is not true. Here are some tips on how to get the first words onto the paper:

  • Lower your standards. Rather than waiting until you have the perfect sentence, it might be better to just write whatever comes to you mind. This way you get some words onto the paper which can help you continue.
  • Write the main essential points in bullet points that you later turn into full sentences. This lowers the urge to make perfect sentences and allows you to restructure your text more easily.
  • Do not worry too much about the first draft. You will most likely rewrite your text several times before you are done anyway (and that is a good thing!).

Many writers do at some point encounter what we call a writer’s block. You have a writer’s block, when you do not know how to start or how to continue writing, and all writing seems impossible. Unfortunately, there is no miracle cure to writer’s blocks. The best way to get rid of the block is to force yourself to write. Some ways to keep writing are:

  • Again: lower your writing standards. Perfectionism can easily kill creativity. Leave perfectionism until you need it.
  • Divide your tasks into smaller steps. The larger the task, the more overwhelming it can be. Try to divide it into smaller steps. For example, focus on one sentence at the time rather than the whole paragraph.
  • Try to write several versions of whatever you are stuck on. There are many ways to write the same thing. By not only limiting yourself to one way, you might free yourself from the block.
  • Revisit the previous paragraph. Sometimes the problem might lie in the text prior to where the writer’s block arose. Check to see if there is anything you can change in the previous paragraph to make continuing easier.
  • Freewrite. Try to freewrite for a set amount of time (5-10 minutes) without thinking too hard or double checking what you are writing. Keep on writing without caring about what goes onto the paper. Afterwards, you can go back and check if you produced any sentences worth keeping.
  • Read other well-written scientific works. One can get inspired to write by reading other’s works. But of course: make sure that you do not end up plagiarizing anyone.
  • Find a writing group or someone to write with. You are definitely not alone if you ever struggle with a writer’s block. Maybe it can help if you sit together with someone struggling with the same and force yourselves to write together?

You can also try to change up your environment, take a break or perhaps discuss your ideas and challenges with other students or colleges. However, remember to make sure that your break or discussion does not turn into procrastination. You must write to get past the writer’s block.

Something that will improve your scientific writing is knowing when to use passive and active voice in your text. Although personal preferences are debatable on this topic, we encourage the general rule to use the active voice as much as possible, but that passive voice should be used when you have reason to do so.

Active voice emphasizes the subject doing an action: the actor (subject) comes before the verb, and the recipient of the action (object) comes after.

The passive voice emphasizes the object receiving the action: the object comes before the verb, and the subject (if mentioned at all) comes after.

 Active voice  Passive voice
 A large number of invertebrates and vertebrates inhabit the ocean.  The ocean is inhabited by a large number of invertebrates and vertebrates.
 Scientists classify sharks as elasmobranchs.  Sharks are classified as elasmobranchs.
 We measured the fish’ total length (cm).  Fish total length (cm) was measured.

The active voice will usually make your sentences shorter and easier to read. It also tends to make your sentences more engaging, vivid and honest. However, there are times when the passive voice is preferable (see below). Some will also argue that it can be nice to vary the voice a bit to make your language less monotonous.

If you are going to publish your work: keep in mind that some journals might prefer more use of passive or more use of active voice. Read articles from the journals where you want to publish to see what they prefer.

When to use the passive voice

  • 1. When the subject is unimportant, unknown or obvious

Passive voice example: Subsamples are often preferred when the total size of the sampled data is too large for efficient data collection.

In this example, the subject is left out. Technically, the subject here would be the research community as a whole, preferring to take subsamples. However we do not need to mention that specifically, because that is obvious and/or unimportant in this case.

  • 2. When the object or action itself is more important than the agent

Passive voice example: Fish total length was measured to the nearest cm.

Passive voice is commonly used in the materials and methods. Here, the one doing the action (the researcher(s)) is not important, but the action itself and the recipient of the action is.

  • 3. When the object is the topic of the sentence

Passive voice example: Ocean surface temperatures are monitored all over the world and have been found to have risen over the past decades.

Who monitors these temperatures (researchers) are not the topic of the sentence, the temperatures are.

  • 4. When the subject is too complex

Active voice example: Atlantic cod, redfish, killer whales, harp seals and several other piscivore predators among various taxa predate on herring.

Passive voice example: Herring is predated on by Atlantic cod, redfish, killer whales, harp seals and several other piscivore predators among various taxa.  

Here, the subject is a long list of species/taxa and the verb is far out in the sentence. This makes it difficult to follow. The sentence becomes clearer and easier to understand by using the passive voice.

Based on: Heard (2016).

You may have noticed that scientific articles use different tenses (times) in different sections. Which tense should you use in which part? Often, that depends on context and partly on taste, but there are some general rules of thumb. For example, it makes sense that most of the Materials and Methods section is written in past tense, because it simply describes the work you carried out (in the past) to come to your results. In other sections, like the Discussion, the answer is less clear cut.


Here, we will go through the main components of IMRaD and review the most commonly used tenses in them. For sake of clarity, let’s start with a quick review of time tenses. There are not three (past, present, future), but in fact 12 tenses, each with their own implication (Table 1).


Table 1. The twelve time tenses in English (mouse over the text for passive voice)
 simple ~  ~ progressive  ~ perfect  ~ perfect progressive
Past I wrote  I was writing  I had written  I had been writing
Present  I write  I am writing  I have written  I have been writing
Future  I will write  I will be writing  I will have written  I will have been writing
Implication Duration is not important Indicates ongoing process through time Indicates a completed action Combining the passage of time and completion of an action.

The Introduction uses a mix of tenses, each tense having their own role. The past perfect is often used to refer to research over time, whilst the present tense is used for current understanding.



1) The effects of microplastics in aquatic food webs have been studied increasingly over the last years.

2) The global climate is changing.

One can even use the future tense, for example when identifying a knowledge gap (often, this knowledge gap is conveniently filled by the current study):

3) A better understanding of the effects of medical waste in fresh water on fish behavior will allow the development of better management guidelines.

Paragraph structure

Paragraphs help communicate your story to the reader by separating different ideas. Ideally, all information within one paragraph revolves around the same topic.

All paragraphs are built up by three main parts: a topic sentence, supporting sentences and a concluding sentence. The topic sentence sets the theme of your paragraph and is commonly the first or second sentence. It introduces the main idea of the paragraph that the following supporting sentences will elaborate on. The concluding sentences give a conclusion to your paragraph based on your supporting sentences.


Transitions within a paragraph

The information in a paragraph revolves around the same topic introduced in the topic sentence, which already improves readability. However, good transitions between sentences are important to add flow to your text and lead the reader in the right direction. Compare these two examples:

Example 1
Paragraphs lacking transitions between sentences can be difficult to read. Paragraphs that have good transitions are often easier to read. Although the information might be the same, including well-picked transitions makes the text easier to process. It is important to make sure that your sentences are well connected to each other.

Example 2
Paragraphs lacking transitions between sentences can be difficult to read. In comparison, paragraphs that have good transitions are often easier to read. Although the information might be the same, including well-picked transitions makes the text easier to process. Therefore, it is important to make sure that your sentences are well connected to each other.

By using transition words and phrases in Example 2 it is easier to understand how the sentences relate to each other and it becomes easier to follow the author’s line of thought.


Transitions between paragraphs

Even though each of your paragraph should have their own theme and main idea, the paragraphs must still be connected to each other to ensure a nice flow to you scientific text. Transitions connects statements and ideas and making good transitions between paragraphs is crucial to aid the reader.

Ways to transition between paragraphs:

  • • By linking ideas. Try to arrange your paragraphs so that the idea of one paragraph can build off the one before.
  • • By using transition words and phrases. Sometimes you can also use transition words and phrases to transition between paragraphs (e.g. first, second, therefore, moreover, similarly), but make sure that these transitions do not result in the reader losing the overview of what the tropic of the paragraph is.

One way to proofread your paragraphs is to look at the last sentence of one and see how it connects to the first sentence of the next.

Be careful with the use of synonyms

In scientific writing the clarity of the text is what is most important. Therefore, you should be careful with the use of synonyms. They can cause unnecessary confusion. Try to use the same terms throughout your text.
Use precise language

When describing numbers and amounts, make sure to use precise language. Avoid using vague terms such as “a large number of” or “considerably less” - these can mean very different things depending on the topic.
The use of abbreviations

There is a difference between abbreviations that is more or less universally accepted, and the ones that are specific to your study. Common abbreviations are for example units (meter = m., litres = l.), months (January = Jan, February = Feb) and some common terms (“and so forth” = etc., “for example” = e.g.).

Study specific abbreviations could be used when you need to shorten down names of specific equipment or treatment types. Make sure to write the word or name in full the first time you use it (with the abbreviation in parentheses), and thereafter you can use the abbreviation throughout the rest of the text. If you are publishing your work: keep in mind that some journals only allow a set amount of abbreviations. Read the journals’ author guidelines carefully.