Writing a paper, results and discussion – day 4: structuring the discussion

Writing a paper, results and discussion – day 4: structuring the discussion

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The key parts of a discussion section

Writing the discussion section well is important to making the most of your research. It is therefore a difficult section to write because you need to make sure that you put across to readers what is valuable about your research and why it matters.

Before you begin there are two key English language items to consider:

The tense to use

When writing about your methods and the items that you carried out in your experiment it will normally makes sense to describe what you did in the past tense. However the discussion section will mainly be full of interpretation and it would make sense in most cases to write that in the present tense.

Active or passive voice

In week 1 the Journal looked at whether it would be best to write your article in the active or passive voice. The convention is to follow the style of your subject if that is established. However, if you were still unsure which way to go then it is worth considering that the discussion will be easier to write in the active / direct form, using ‘I’or ‘we’ for you or your team. Not only is it more direct and therefore clearer, but you are likely to be comparing with other studies written by other authors and in that situation it could become difficult for the reader to understand which paper is being referred to with the passive voice.

Two other key aspects to writing a discussion are:

  • Avoid repetition and do not repeat the results.
  • Avoid putting all of the literature references in the discussion, it will become too full and hard to read.

What to include

So what should go in the discussion? If you follow the items below and make sure to cover them in the discussion, while also remaining succinct and to the point then you should be able to write a useful section. Being able to use this list will hopefully enable you to focus on writing good English. You can use some of the phrases from the Journal this week to address the points below.

  • What are the most important findings?
  • Do the findings support the hypothesis?
  • How do you interpret the results and what other interpretations should be considered?
  • What are the limitations of the study, what other factors should be considered that could have influenced the results, what exceptions and flaws should be noted?

The following items could be in the results section, but could also go in a separate conclusion section if you have one.

  • Do your interpretations add to the knowledge and understanding in the field and do they advance or challenge other work – what is the significance?
  • What is the relevance to other areas?
  • What are the theoretical implications and practical applications?
  • What further research should be done?

Have a read through the discussion extract below, where we have published various sentences from throughout the section to show some of the main points covered. You can read the full section here.

Childhood body mass index trajectories and associations with adult-onset chronic kidney disease in Denmark: A population-based cohort study


Men and women with childhood BMI trajectories above average had higher rates of CKD compared to individuals with the average childhood BMI trajectory, even when including the development and duration of adult T2D in the analyses.


Although the trajectories investigated in our study are not directly comparable with those in the British study due to differences in ages examined and how the trajectories were created, both studies consistently found that patterns of early life BMI development that include overweight are important in relation to CKD risk.


The biological mechanisms underlying the associations between excess adiposity and CKD are likely multifactorial and complex but are not fully understood. The main factors suggested to explain these links include the alterations of renal or systemic hemodynamics (including hypertension), adverse metabolic effects such as insulin resistance and chronic inflammation, and renal lipid accumulation, all contributing to kidney damage. Another potential explanation is the tracking of body size, as it has been shown that excess adiposity at childhood ages is likely to track into adult ages.


Our study also has some limitations. Our follow-up period spans several decades; thus, it is likely that diagnostic changes have occurred as well as changes in the awareness of CKD by healthcare providers. We did not have a high and systematic coverage of laboratory tests available during the follow-up period; thus, we were unable to include estimated glomerular filtration rate or albuminuria levels in the case ascertainment as recommended by the Kidney Disease Improving Global Outcomes guidelines.


With a worldwide growing population of children with overweight and obesity, our findings highlight the importance of continued efforts to attain or maintain a healthy weight and further add to the understanding of CKD disease etiology and potential modifiable risk factors.

This extract is from: Aarestrup J, Blond K, Vistisen D, Jørgensen ME, Frimodt-Møller M, et al. (2022) Childhood body mass index trajectories and associations with adult-onset chronic kidney disease in Denmark: A population-based cohort study. PLOS Medicine 19(9): e1004098. https://doi.org/10.1371/journal.pmed.1004098

Useful phrases from the extract

had higher rates of CKD compared to: highlights the main finding of the study with a comparative.

are not directly comparable: the comparison with other studies

both studies consistently found: showing the similarity of results with other studies

are likely multifactorial and complex: interpreting the findings – which is ‘complex’.

not fully understood: highlights limitation of knowledge

The main factors…. to explain these links include: interpretation with caution

Another potential explanation: giving alternative explanations

has some limitations: describing the limitations of the study

did not have… systematic coverage: describing a limitation

our findings highlight the importance of: in a concluding paragraph the most important finding is restated

further add to the understanding of CKD disease: and the advance in knowledge is also stated

Further study for this week

This week you can try to write a results or discussion section describing the main findings of a recent study. Try the short quiz below to test your understanding.

Lesson tags: English for scientists, Results and discussion, structuring the discussion, writing a paper
Back to: English for Scientists