How to write a good conclusion in a scientific paper

To write a good conclusion, we need to make three points. First, we need to round up the paper, give a quick summary. Second, we need to point out limitations and how to address them. Third, we should leave on a positive note. While a summary is part of almost every conclusion, we observe that limitations and positive notes are often swapped out for future applications. But this is not a good idea, as I will illustrate to you.

Let us assume I am writing a paper about building a novel stone plate. When finishing the paper about my stone plate, I might give you a typical future-application conclusion. In a future-application conclusion, I quickly summarize my paper and then give you possible future applications. In my stone plate case, I would end by pointing out how my novel stone plate allows you to build houses, cathedrals or even a harbor.

But that approach is not very informative. If you read a paper about building stone plates, you most likely know exactly what you want to accomplish. Maybe you want to build an aqueduct and want to know if those stone plates are strong enough. Maybe you want to build a stove and want to know if those stone plates will sustain the heat. Maybe you want to build a shielding against rain and want to know if those stone plates develop cracks over time. When reading a paper, you do not want to know what you can do with it, but when it breaks.

Instead of frustrating your audience, you should use the conclusion to state all the limitations. Limitations are the fence around your paper, they show how far you have conquered the topic. For each limitation, you should provide a way to push the fence. If the stone plate is not strong enough, maybe we need to make it thicker. If the stone plate does not sustain heat above a certain temperature, maybe we need to add a protection layer. If the stone plate cracks easily, maybe we need to use a more refined mixture. Anyone extending your paper will have a pointer of where to go. Think about it like a signpost.

Once that work is done, leave on a positive note. One sentence or paragraph suffices, like “Our new stone plates could, however, be an essential element to build long-lasting, rain and heat-shielding structures.” This sentence services two purposes. First, it puts the narrow focus of your paper in the broader context of human life and society. It shows that you are contributing to the well being and advancement of civilization. Second, it evokes a positive emotion. The reader can put the paper down and dream about the possibilities your work could realize. The sentence is broad enough so that almost every human being can project their own imagination onto the “long-lasting structures”.