How to Write the Discussion for a Scientific Paper


In a recent Twitter poll, I asked which major section of a scientific paper is most difficult to write. As you can see, of the 241 respondents, 57 percent voted for the discussion and 33 percent for the Introduction. And only a handful voted for methods or results. I've already talked about how to write an introduction in another video. So in this video, I'm going to tackle the Discussion. First, let me emphasize the importance of taking time to read the literature to get a clear picture of your topic before attempting to write your discussion. This may seem obvious, but if you are having trouble getting started, it may be a sign that you need to do some more preparation. Your goal in writing the discussion is to explain to the reader your results and how they agree with or deviate from work previously reported in the literature. Don't just restate the results with a few references to the literature sprinkled here and there. You must interpret the results and back up that interpretation with a reasoned argument and relevant citations. Let's now consider how the discussion is structured and look at an example. Similar to the Introduction, there is a general formula for writing the discussion. There can be variations on this formula, but the discussion should contain three basic parts. A brief overview section to reorient the reader, a critical and detailed analysis of the findings, and implications or significance of the work. Let's look at an example. This is a paper I wrote about how herbaceous coastal plants facilitate mangrove reestablishment in a clearcut forest. In this particular paper, I began the discussion by pointing out that facilitative interactions occur in a variety of plant communities, which quickly reorients the reader to the main topic. I then explained why a manipulative experimental approach was necessary to demonstrate plant facilitation and provided examples from the literature. You also want to remind the reader of the main finding, which in this example came in the second paragraph: In our investigation, herbaceous vegetation clearly facilitated recolonization of mangroves in a disturbed forest.

The next paragraph summarized three mechanisms whereby such facilitation may operate. Trapping propagules. Promoting rooting. And ameliorating soil factors. That list foreshadowed how the remaining discussion would be structured. The second section of the discussion should provide an in-depth interpretation of the findings. Depending on the complexity of your study, this part of the discussion may be divided into subsections, each focused on a different experiment or process studied. If you conducted three experiments, for example, you could create a subsection to discuss each one in turn. Or, you could divide the discussion according to three processes studied. In my example, I divided this part of the discussion into an examination of the three mechanisms mentioned in the opening section. I combined the first two mechanisms and titled the first subsection accordingly. Facilitation of seedling establishment through propagule trapping and structural support. The next subsection focused on the third mechanism, amelioration of physicochemical conditions, which was discussed in detail and in relation to what others have found. The number and arrangement of such subsections will obviously vary from paper to paper. And some discussions have no subheadings, but should still be organized in a logical sequence. No matter how you organize these subsections, the idea is to interpret your main results and compare them with what other investigators have found. Typically, there will be other work that agrees with your findings. However, you should also acknowledge work that disagrees with yours and discuss why you think there is a difference. The reason might be methodological or perhaps the systems studied differ in some fundamental way. For example, I pointed out a difference between our findings and those reported for another location and suggested several reasons why.

Doing so helps the reader see how your work fits in with what is known, but also suggests potential areas for future research. Let me mention one more important component of your critical analysis section, and that is the limitations of your study. All studies have limitations. Was your study conducted in a single geographic location? Did the experiment last long enough to detect an effect of the treatment? How did your sample size affect the outcome? You must carefully and honestly assess such limitations and discuss them. Some authors discuss limitations in a separate section of the discussion. Others point out specific limitations and strengths as they arise in the discussion. The decision is made based on the specifics of your study as well as the traditional approach used in your particular field. In my example, I talked about limitations to assessing plant facilitation in the opening section of the discussion. Normally, you do not want to start off your discussion by listing the study's limitations, but in this case, I did so to explain the tradeoffs involved in different approaches so that the reader could better understand the interpretation of the results. The final section of the discussion should wrap things up, for example, by pointing out the implications of the work or any applications. In my example, I ended the discussion with a section called implications for mangrove restoration in which I pointed out how future work could build on ours. In deciding on a structure for your discussion, it helps to look at other papers published in your target journal. Spend some time reverse-engineering their discussions. You can easily do this by outlining each one, which will reveal the hidden structure. To summarize, a good discussion should follow a basic three-part formula: an opening segment putting the work into the big picture, a critical analysis of the study findings, and potential consequences or applications.

Of course, there are multiple ways to structure a discussion. I've presented one way that has worked for me. If you are having trouble getting started, my formula may help. Once you get some experience, you can develop your own writing formula But by following a logical formula, you can write a compelling and informative discussion for your paper. Thanks for listening and please like my video if you found it helpful. .