When and how to summarize sources

During your research, you might come across an entire source, chapter or longer section of text that is relevant and interesting to your own study. In that case, rather than simply pull out one quote or paraphrase a particular section, you may wish to summarize the source in its entirety.

What is summarizing?

A summary is a condensed but broad overview of the content within a source, written in your own words. A summary is typically much shorter than the text from where the information is taken.

Think of an academic summary like a movie synopsis you might read to gain a quick understanding of the key plot points, characters, climax and resolution. Your goal is to provide the reader with a clear understanding of the source in a concise way.

Once they read it, they should be able to accurately understand the information the source is conveying, without missing any of the key points.

Example of summarizing

For this example, we will use a feature article published by the BBC: “How bacteria are changing your mood.” To fully understand how we have summarized the information, it would help to read the complete article yourself.

Now, here is the summary:
A 2018 article published by Gallagher outlined how numerous researchers are exploring the ways in which bacteria present in the gut – the microbiome – can influence human thoughts and emotions, and thereby conditions such as autism, depression and neurodegenerative disease. The pioneering study (Sudo et al., 2004, cited in Gallagher, 2018, para. 79) conducted at Kyushu University found a significant disparity between mice that had never come into contact with microbes and those that had, with “germ-free” mice producing twice the amount of stress hormone. Since then, further research into the phenomenon has found, for example, that clinically depressed patients often have less diversity in microbiota, and that transferring microbiome from persons with Parkinson’s disease to mice significantly influenced the animals’ symptoms and behaviour. The findings in extant literature indicate a positive direction for the future of both physical and mental health, with researchers now examining the role of microbiome in various diseases, including allergies, cancer and obesity (Gallagher, 2018).
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Summarizing versus paraphrasing

While a summary is a complete or partial description of a source, paraphrasing is when you explain a particular section of text in your own words. Paraphrasing is almost a mixture of quoting and summarizing, as the final product will contain the same information and be roughly the same length as the original text, but in different wording.

Examples of quoting, paraphrasing and summarizing

From the DutchNews.nl article: “Polish community in NL”, 2018
Quoted text“Despite having jobs and working long hours, Polish nationals earn on average a third less than the Dutch and 17% live in poverty. However, just 1.8% are claiming welfare benefits, compared with 2.6% of the Dutch population as a whole” (DutchNews.nl, 2018, para. 5).
Paraphrased textPolish expatriates living in the Netherlands earn one-third less than Dutch workers on average. While 2.6% of the nation’s population claim welfare benefits, only 1.8% of Polish nationals do. 17% of Polish nationals in the Netherlands live in poverty, though they work long hours and hold regular jobs (DutchNews.nl, 2018, para. 5).
Summarized text (entire article)The results of a 2018 survey by the Social and Cultural Planning Office (SCP) published on DutchNews.nl found that, of the 160,000 registered Polish expatriates residing in the Netherlands, 75% are more likely to have irregular employment contracts, work long hours or undertake manual labour. Industries such as agriculture and horticulture are heavily reliant on Polish nationals, but 17% live in poverty and, on average, the average Pole earns one-third less than a Dutch person. The survey results stated that, while 2.6% of the entire population of the Netherlands claims welfare benefits, only 1.8% of Polish expatriates do. Despite a rise in experiences of discrimination from 38% in 2009 to 46% in 2017, Polish expatriates rate their life in the Netherlands at an average of 7.1 out of 10 (DutchNews.nl, 2018).

When to summarize

You should summarize a source when the broader concept covered throughout is highly relevant to your own research.

When to quote, paraphrase and summarize
Use a direct quoteWhen you find a perfectly worded section of text, comprised of a few sentences or less
Paraphrase the original quoteWhen you find an interesting idea of one paragraph or less that does not need to remain in the original wording to convey the information in the clearest, most powerful way
Summarize the entire study, chapter or pageWhen you find a complete study, chapter, page or even more than one paragraph that is relevant to your own research, with several interesting ideas you would like your reader to be aware of

Should you summarize? Ask yourself:

  • Is the complete idea interesting and relevant to your study, but too long to paraphrase or quote (i.e. longer than one paragraph)?
  • Does your reader need to understand all of the information in order to appreciate your study?
  • Did the specific study help define your own research more than any other?

If you answer yes to any of these questions, you should probably summarize that source rather than paraphrasing or quoting.

How to summarize

Step 1Read the entire text carefully. A good summary will require you to be very familiar with the source material so you can draw out the key points
Step 2Identify the core theme of the text
Step 3Think about the most important ideas and identify the main points to be shared in your own summary. Take notes if you need to
Step 4Rewrite the main points in your own words
Step 5Reread your own text and be sure it is not too similar to that of the original. Change any phrases possible that remain too closely matched

How to cite when summarizing

Introduce your source immediately

As you will note in the two examples, the source from which the information for the summary was taken was immediately introduced. This lets your reader know they are about to read a summary of information from a particular source.

Here are some ways you can introduce your source at the start of a summary:

  • According to research by the Social and Cultural Planning Office published in 2018, …
  • In 2018, the Social and Cultural Planning Office released the results of a survey…
  • In a 2018 study, the Social and Cultural Planning Office found…

Refer to the source throughout the summary

Depending on how long your summary is, it may be wise to remind or confirm to your reader that they are still reading information from the same source introduced at the beginning.

In our example on Polish workers in the Netherlands, it was enough to include the introductory mention and in-text citation at the end because this was just one small paragraph. If your summary is any longer, you can add another citation (as in our first example) or mention of the source.

Example of multiple citations in one summary
A 2018 article published by Gallagher outlined how numerous researchers are exploring the ways in which bacteria present in the gut – the microbiome – can influence human thoughts and emotions, and thereby conditions such as autism, depression and neurodegenerative disease. The pioneering study (Sudo et al., 2004, cited in Gallagher, 2018, para. 79) conducted at Kyushu University found a significant disparity between mice that had never come into contact with microbes and those that had, with “germ-free” mice producing twice the amount of stress hormone. Since then, further research into the phenomenon has found, for example, that clinically depressed patients often have less diversity in microbiota, and that transferring microbiome from persons with Parkinson’s disease to mice significantly influenced the animals’ symptoms and behaviour. The findings in extant literature indicate a positive direction for the future of both physical and mental health, with researchers now examining the role of microbiome in various diseases, including allergies, cancer and obesity (Gallagher, 2018).

Include an in-text citation

Even though you have already mentioned the source, you must finish the summary with an in-text citation as per the rules of your citation style.

Note that one in-text citation at the end of a summary, without having introduced the source to begin with, will not satisfy the requirements of proper citation.

Completing a plagiarism check

When you have finished writing your dissertation, you may wish to complete a plagiarism check to ensure you have summarized, paraphrased and quoted all of your sources correctly. This detailed scan of your thesis will tell you if any of your text is too similar to the original sources, setting your mind at ease before your submission deadline. This final check will be particularly useful if you have summarized several sources.

Checklist: Summarizing correctly

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Courtney Gahan

Courtney has a Bachelor in Communication and a Master in Editing and Publishing. She has worked as a freelance writer and editor since 2013, and joined the Scribbr team as an editor in June 2017. She loves helping students and academics all over the world improve their writing (and learning about their research while doing so!).

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