Reaching conclusions: differences between the Abstract and the Conclusions section

Geoffrey Hart

Previously published as: Hart, G. 2020. Reaching conclusions: differences between the Abstract and the Conclusions section. <https://www.worldts.com/english-writing/eigo-ronbun70/index.html>

Like the “punch line” to a joke (the part that makes you laugh), or the solution to a mystery novel (when the criminal’s identity is revealed), the Conclusions section of a scientific journal manuscript is where you tell the reader what all your results (presented in the Results section) mean and the consequences of your discussion of those results (in the Discussion section). In short, this is where you summarize everything the reader has read, as concisely as possible, by telling the reader what messages they should remember and what should happen next.

Because the Abstract of a paper provides much of the same information, it’s natural that many Conclusions sections end up strongly resembling the Abstract. Some of this overlap and repetition is necessary, but some of it results from not understanding the different purposes of the two sections and the resulting differences in their focus. To help you write the Conclusions section, I’ve provided a list of contrasts that show the difference between the two sections and what your priorities should be when you write them:

Purpose: The Abstract should provide a concise summary of your findings, with an emphasis on key quantitative details. It’s only a slight exaggeration to say that reading a well-written Abstract provides as much understanding of the research as reading the whole paper, though obviously at a much lower level of detail. The Conclusions should also summarize your findings, but with an emphasis on their meaning and implications rather than on repetition of the quantitative details.
Length: The Abstract is usually limited to 200 or 250 words, which requires you to be extremely concise and to carefully choose only the most important details. You don’t have enough room for more detail. In contrast, the Conclusions can be significantly longer if your study was large or complex and had many findings. This does not mean you should be verbose: concision is still important. But it does mean you have more freedom to explore key details than you do in the Abstract.
Contents: The Abstract should report all or most of the key quantitative results that you presented in the Results section or discussed in the Discussion section. In contrast, the Conclusions should describe only the meaning of those findings rather than repeating numerical data that you have already presented two or three times (i.e., in the Abstract, the Results, and the Discussion). For example, the Abstract might include the following: “We obtained crop yields of 10, 20, and 30 g/m², respectively, in the control and in the treatments with 2× and 3× the control fertilizer level.” In the Conclusions, you would instead write the following: “Crop yield increased with increasing fertilizer application.”
Relationship to goals: The Abstract does not relate your results to the goals you defined for your study. There’s no reason you cannot do this, but the limited length of this section often means that you don’t have enough space to describe both the goals and the results that support those goals. In contrast, the Conclusions section should describe whether you accomplished your goals and, if not, what should be done in future research to accomplish those goals.
Relationship to hypothesis: Once again, the Abstract usually does not have room to state your hypotheses. There is rarely enough space to do more than describe the problem that you studied. In contrast, the Conclusions section gives you enough room to repeat your hypotheses and explain whether you confirmed or rejected them. Thus, you should clearly indicate which hypotheses you confirmed and which you rejected, and clarify what this means for future research.
Focus: Both the Abstract and the Conclusions focus on your results. Thus, neither section should include citations for research by other researchers or descriptions of specific previous results. However, it’s acceptable in both sections to state whether you confirmed previous results or whether you discovered a contradiction that must be explained. The only exception is when your paper is a comment on or criticism of a previous study. In that case, it’s acceptable to provide a literature citation, though in the Abstract, that citation must include the authors, year, journal name, volume number, and page range, and perhaps the DOI for the paper. Why? Because the Abstract is often published separately from the rest of the paper, and a reference such as “(Hart 2018)” would be difficult for readers to find without these details.
Novelty: In both sections, it’s important to state what is novel (new and innovative) about your research. In the Abstract, this tells the reader why they should continue reading the rest of your paper rather than stopping after the Abstract. In the Conclusions, this reminds the reader why your paper is important.
Consequences: In the limited space available in the Abstract, you usually cannot provide much description of the consequences of your research, other than in brief terms. For example, “These results will support efforts by plant breeders to improve crop yield.” In contrast, you have room in the Conclusions to describe in some detail what work remains to be done to clarify your results and what problems need to be solved in future research. (This information can also appear in the Discussion, but it is legitimate to provide this information in the Conclusions instead.)

In conclusion, there are clear similarities between the Abstract and the Conclusions section, but once you understand their different purposes, it’s not hard to differentiate between the two.