There are basically two main summarization techniques, and they are known as extractive and abstractive summarization. In this post, we will look at both of these techniques in detail and use examples to show how both of them work.
And then, we will describe the working of online summarizer tools in the light of these two techniques. Let’s get started.
What is Summarization?
Let’s begin with defining what summarization is.
Summarization is the process in which a particular piece of content is shortened so that its main idea and theme are understandable, but the overall length is substantially reduced.
Different types of writers use summaries. For example, bloggers can write summaries when they have to provide their readers with an excerpt about a particular post. Similarly, book authors can write summaries when they want to give a synopsis of the contents.
What is Extractive and Abstractive Types of Summarization?
Abstractive and extractive summarization are two techniques of creating a summary. Let’s take a look at them one by one:
In extractive summarization, the summary is created using sentences from the original content. In other words, the summary is not written from scratch. And rather, different sentences from the existing content are taken and put together.
The benefit of this technique is that you don’t have to make an effort to create a summary yourself. And you can take meaningful sentences from the existing content and piece them together.
The downside of this technique is that since you are just putting together existing pieces of content rather than creating it from scratch, there can be a sort of abruptness and patchiness in it.
Let’s look at an example to understand this type of summarization. Here is an example paragraph that we will summarize using the extractive method:
The baboon could not find his banana. He searched the entire jungle. Soon, he came across a banana peel. Without seeing it, he stepped on it, and he slipped and fell down. As he saw the peel, he realized it was his now-eaten banana. He began to cry. But then, he looked up and saw that the trees in the jungle were all banana trees. He started shrieking in delight.
So, this is an example paragraph. Now, let’s create a summary by only extracting some lines from it and piecing them together:
The baboon could not find his banana. Soon, he came across a banana peel. He began to cry. But then, he looked up and saw that the trees in the jungle were all banana trees.
Now, this is around half the length of the original passage. Usually, the summary should be around 10% of the text, but since we were only working with a paragraph. This is about the lowest we can go.
As you can see in the summarized version, the same sentences are used. And the overall idea and concept of the content are also relayed without much problem.
Abstractive summarization is the technique of summarizing in which the content is understood and then rewritten using completely different words and phrases. The content idea is relayed by creating a unique and new summary.
The benefit of this type of summarization is that since you create the summary from scratch, you can make it through and flow nicely.
The downside of this summarization is that you have to make an effort to write the summary instead of just using the existing sentences.
For example, we will use the passage above…the one about the confused baboon.
The baboon could not find his banana. He searched the enter jungle. Soon, he came across a banana peel. Without seeing it, he stepped on it, and he slipped and fell down. As he saw the peel, he realized it was his now-eaten banana. He began to cry. But then, he looked up and saw that the trees in the jungle were all banana trees. He started shrieking in delight.
Here is what the abstractive summary of this content would look like:
The baboon failed to find his banana in the jungle. He then slipped on a banana peel, which he realized was his banana. He was sad, but then he saw that all the trees in the jungle were banana trees, which made him happy.
As you can see in this summary, the words used differ from those used in the original text. That is because here, we did not create a summary using the sentences from the actual passage. Rather, we understood the main idea and then wrote it in our own words.
The Working of Online Summarizing Tools
Now that we are clear on the two types of summarization techniques. Let us discuss the working of online text summarizer tools.
Online summarizing tools usually (in the vast majority of the cases) work using the extractive method. In other words, a summarizing tool will analyze the given content and then piece together some sentences from it to create a summary.
Although there may be some tools online that use the abstractive technique, there are none that we know of at the moment. This sort of functionality is, by the way, not too difficult to imagine in this AI-driven, digital age.
For one, a tool is available online that changes their arrangement and structure despite using the original sentences. For example, this tool will merge sentences when creating the summary.
So, coming back to the point, most online tools use the extractive summarizing technique to create summaries of the entered content. In this regard, the tools’ quality and efficacy are determined by their intelligence in understanding the meaning of the content. And then picking on the most meaningful sentences to create the summary.
In other words, it will not be a good tool if the summarizing tool takes a bunch of random sentences from the content that do not properly describe the main idea and concept.
Before wrapping up, here is a screenshot showing how a summarizer will create a summary using the extractive method:
To sum it up, there are two types of summarizing techniques, i.e., ‘Abstractive’ and ‘Extractive’.
Extractive summarization entails using existing sentences in the content to create the summary. Whereas the abstractive technique entails explaining the concept using different words.
When it comes to online tools, the majority of them use the extractive technique.