If you’re a university student with lots of assignments, you’ve probably heard of Turnitin. If not, don’t worry—you’ll be familiar with it by the end of this article.
Turnitin is one of the most popular tools for plagiarism detection, not just in the UK but worldwide.
As this is such a widely used—and likely one used by your university, it’s important to learn more about it and how it works.
In this article, we’ll be breaking down Turnitin and going through what it does, how it works and how to use it. Plus, we’ll even look at how accurate it is and how it works for AI content.
Table of Contents
What is Turnitin?
When we mention Turnitin, we’re usually referring to the plagiarism detection software it’s famous for. However, Turnitin is the name of the company itself, which offers several different products. This includes its well-known plagiarism tool, as well as a range of other resources.
The Turnitin tool that is used for plagiarism detection is called Similarity. While it does work to prevent plagiarism and aids in its detection, this software just finds the extent of similarity between the submitted assignment with other texts within Turnitin’s database. You can learn more about this in this article from the Turnitin blog.
Turnitin products, especially the Turnitin Similarity software, are used by countless universities. Some examples include the University of Leeds, the University of Illinois at Urbana-Champaign, and San Diego State University. You can see more examples of universities that use Turnitin on this page of the Turnitin website.
Turnitin is used due to the range of resources it provides. Primarily, universities use it to help them with plagiarism detection.
While its primary use is for plagiarism detection, Turnitin can also help with referencing, assignment feedback, and even grading assistance. You can learn more about the uses of Turnitin by checking out this article by Uni Compare.
How does Turnitin detect plagiarism?
As previously mentioned, the Turnitin product used for plagiarism detection is called Similarity. This software aids in plagiarism detection but isn’t a detector of its own.
Instead, it works by finding similarities between the submitted assignment and other texts within Turnitin’s database. This database is incredibly large and varied as it includes over 40 billion web pages, almost 2 billion student assignments, and more than 100 million articles.
Using all this data, it then creates a similarity report and gives your assignment a percentage score to show how similar it is to the Turnitin database. You can learn more about the Turnitin Similarity software on this page of the Turnitin website.
As Turnitin is only detecting similarities, it is then up to university officials to interpret if there has been plagiarism or not. A high score of similarity doesn’t necessarily mean that there has been plagiarism, and a low score doesn’t mean that there hasn’t been. Turnitin Similarity is only there to make the process quicker and easier. Learn more about how Turnitin works in this article from the Turnitin blog.
What Turnitin score is acceptable?
The Turnitin Similarity software crosschecks a multitude of different sources to detect similarity. Once it has finished detecting the similarity levels, it produces a report, which includes a percentage score to show how much of the assignment is similar to other papers.
The similarity score is calculated by dividing the number of words within the paper by the number of words that have been flagged as similar to other sources.
In the Similarity Report, you will find your submission colour-coded based on the degree of similarity:
- Green: 0% similarity
- Blue: 1% – 24% similarity
- Yellow: 25% – 49% similarity
- Orange: 50% – 74% similarity
- Red: 75% – 100% similarity
Since Turnitin is a similarity checker, not a plagiarism checker, a high score doesn’t mean that there has been plagiarism, and a low score doesn’t mean that there hasn’t been any. This is because Turnitin flags anything that matches other sources, including correctly cited quotes and ideas. So, even if you’ve done your referencing perfectly, those direct references will still be marked as similar.
Learn more about how the Turnitin Similarity report and score works on this page of the Turnitin website.
However, even if there’s no plagiarism involved, a high similarity score might mean you’re relying too much on direct quotes. Due to this, it can be a good idea to aim for a score of around 15%-20%. On the flip side, if your similarity score is 50% or higher, it’s worth revisiting your work to double-check for potential issues and ensure everything is properly cited.
For more on this, have a look at this page on the National College of Ireland Library’s website.
Is Turnitin accurate?
As useful as it is, Turnitin is not a perfect resource. It has several key drawbacks that affect how effective it is for checking plagiarism:
- As Turnitin is a similarity detector rather than a plagiarism one, it flags all similarity. This means that certain instances couldn’t possibly be plagiarism but will still be highlighted for similarity.
These include:
- Fully cited quotes and intertextual references.
- Some common words and phrases will automatically be flagged. However, it is possible to customise the software to exclude these.
For more on the limitations of Turnitin, have a look at this article from Quetext.
- Turnitin doesn’t distinguish between your own submission and similarities with other texts. Due to this, you may end up receiving a score of 100% similarity if you submit more than one draft of the same work.
This is because Turnitin uses students’ submissions as part of its database, meaning each new submission is automatically crosschecked against previous ones.
As a result of this, you can’t use Turnitin to track improvements in your work, as submitting multiple drafts will lead to a high similarity score. Turnitin’s recommendation to avoid submitting multiple drafts therefore acts as a significant drawback, majorly reducing its accuracy rates.
You can learn more about this on this page of the Turnitin website.
- Since the AI detection service was only developed in 2023, its use is more limited compared to Turnitin’s standard plagiarism detection software. However, we’ll explore this in greater detail in the next section.
Can Turnitin detect AI-generated text like ChatGPT?
Turnitin launched its AI writing detection service in 2023. Therefore, Turnitin can detect AI-generated text, including ChatGPT. However, from January 2024, institutions will need to be subscribed to the Turnitin Originality software to access this feature.
Learn more about the development of this service on this page of the Turnitin website.
This AI detection tool works by splitting the submitted paper into segments and running each of these against their AI detection model. From here, each segment is given a score, which is then combined to give the paper its overall score. You can learn more about how this process works by looking at this page of the Turnitin website.
Like Turnitin’s other products, the AI writing detection service is popular amongst education providers to ensure academic integrity. However, it does have some notable limitations:
- Inconsistent accuracy: Turnitin’s AI writing detector may incorrectly flag AI-generated content, from the likes of ChatGPT as being written by a human, or human-written content as being generated by AI.
- Limited to prose: Turnitin’s AI detection service only works on prose writing, meaning that it cannot analyse other formats such as scripts, poetry or code.
- Does not detect short-form content: Bullet points, tables or bibliographies are not evaluated by its AI detection tool.
- Specific requirements: The Turnitin AI detection has stricter requirements compared to other tools, including limited language options (currently only English and Spanish) and restrictions on word count and writing formats.
You can learn more about the limitations of Turnitin’s AI writing detector on this page of the Turnitin website.
Can Turnitin detect paraphrasing?
Paraphrasing is where you use a source, put it into your own words and summarise it. When making direct or indirect references to certain sources, paraphrasing can be very useful in your work.
Turnitin can detect paraphrased content by detecting similarities, but this doesn’t necessarily indicate plagiarism. Even when the wording has been changed, paraphrased content may still appear similar to the original source, so it’s only natural for it to be flagged.
AI-generated paraphrasing is another type of paraphrasing. Simply put, Turnitin’s AI detector can also identify content that has been paraphrased using AI. This is done using the same system that detects general AI-written content.
Due to this, it has the same limitations and will sometimes produce inaccurate results. For example, it may also struggle to identify whether short-form content, such as bullet points or tables, was generated using AI.
You can learn more about this on this page of the Turnitin website.
Regardless of its ability to detect paraphrasing by similarity or from AI, you should make sure that you are ensuring academic integrity in your work. This is to say that you should paraphrase without plagiarising.
Look at the following tips to help you paraphrase effectively:
- Use AI responsibly: If you need to, use AI to paraphrase a text to help you generate your ideas, but you shouldn’t use this content directly in your own work.
- Treat AI content as inspiration: Create your summary or paraphrased content using AI-generated content as a starting point for ideas, but don’t solely rely on it.
- Focus on key points: When paraphrasing, make sure you use your own words and are concentrating on capturing the main ideas.
- Always cite your sources: Even if paraphrasing or summarising, ensure that you properly cite and fully reference the original sources.
For more tips on paraphrasing, have a look at this article by Wordtune.
Can Turnitin detect tools like QuillBot?
As previously mentioned, Turnitin can detect AI-generated paraphrasing. This is still the case even if a word/article spinner tool was used, such as QuillBot, Word AI, Spinbot, Wordtune or similar alternatives.
A word spinner is a type of paraphrasing tool specifically designed to reword and alter text with the intention of evading plagiarism. These tools are powered by AI and can produce content that closely resembles the original. As a result, using tools like Quillbot will be flagged for both AI similarity and paraphrasing similarity. Due to this, you should be careful when using these tools and use them responsibly.
Once again, it is crucial that you are fully referencing your sources to avoid plagiarising.
You can learn more about these in this guide by Turnitin. For more examples of word spinner tools, have a look at this article by Khris Digital.