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Abstract vs. Introduction: What’s the Difference?
The main difference between and abstract and an introduction is that the abstract is a brief summary of your entire study—the aim or objective, methods, results, and conclusions—usually in that order. It gives the highlights of your work, with only the briefest background information.
In contrast, the introduction includes only some elements of what is in an abstract. In the abstract, you will expend the fewest words possible on the aims or objective section that opens it, just enough to let your reader know your research question. In the introduction, you will expand on the trail of evidence that led you to asking your research question.
What is an abstract for a research paper?
In an abstract, you summarize your work and capture the reader’s attention with the most important details about your work. Usually, you must give this information in 250 words or fewer.
The contents of the abstract
In just a couple of sentences, you start by giving your readers the background and objectives or specific aims, in just a few sentences. You then will give a few important details about the study design, number of participants or animals, treatments or interventions, controls, and so on. Then you will give the reader the most important results from your study, and end with a conclusion that communicates the most significant takeaway from those results. The language of the abstract should be as clear as possible, even to a nonspecialist.
You can find more specific information and examples of what to include in your abstract here, in this post, “How to write an abstract for a research paper.”
What is the introduction of a research paper?
The introduction to a research paper orients your reader to the context of your study. It gives the reader just enough background to understand why you’re doing the work. Many journals require authors to keep introductions quite brief, limiting them to only 500 words or fewer in some cases. Even if a journal does not limit the length of the introduction, you should still try to be as concise as possible.
In this part of your paper, you will give the reader the chain of evidence that led you to ask the central question or questions of your study. This part of your paper does not need to give every single detail or cite every study in the field. You need only to walk the reader through the evidence that leads to your own study question or hypothesis. Usually, you will being with a general statement and then funnel down from that to your specific research question. For more specific information about writing introductions, see the blog post, “How to write a great introduction to a research paper.”
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7 differences between an abstract and an introduction
1. An abstract will include results. An introduction will almost never include results. At most, depending on the journal, you might give a sentence generalizing your findings.
2. An abstract will offer a conclusion. An introduction will almost never give the reader the main takeaway from the study findings.
3. The abstract will give some details about the methods and study design. The introduction will offer only the briefest information, such as “Here, using mice” or “In this study of patients with breast cancer.” Any details, including numerical values, will be reserved for the materials and methods section of the paper.
4. The abstract will have only a brief background section, usually consisting of a sentence or two, at most. The introduction, in contrast, will unfold this background succinctly but more expansively, giving the reader the context for why you asked the research question you did and the trail of evidence that has led to the study you performed.
5. The language in an abstract will likely be more accessible to nonspecialists reading the paper. You should avoid jargon and abbreviations as much as possible, and try to communicate your information as briefly and clearly as possible. The introduction, on the other hand, can be offer more details of interest to people in your field, and using abbreviations is OK.
6. An abstract will almost never contain reference citations. An introduction almost always will.
7. An abstract will usually run 250 words or fewer. Although some journals limit introductions to no more than 500 words, in many journals, the introduction can be longer.
A very few highest profile journals have some submission options that use the abstract as the introduction to the paper. These journals usually call these submission categories “Letters” or “Short submissions.” In such cases, the abstract serves as the introduction to the paper and is given as a fully referenced paragraph that both introduces the work and summarizes the results and design. You will know if this special merging of the abstract and introduction is a requirement if you consult the author instructions of your target journal.
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