A Teacher's Guide to Spotting AI-Written and Plagiarised Work in 2026

The rise of AI has raised new concerns about plagiarism at every educational institution.

While the availability of various AI tools can feel concerning for educators and parents, a survey spanning 15 years, on four separate occasions, showed a downward trend in plagiarism.

However, this was no isolated incident, and indicators showed that this was caused by tightening plagiarism prevention policies through the integration of a specific detection tool in their learning management systems.

This just goes to show that in 2026, upholding academic integrity depends on how tightly educators are monitoring students’ learning behavior and maintaining a strict policy that prevents plagiarism.

So, while there’s an increase in ways a student can plagiarise, teachers need to stay one step ahead to ensure that students do not use unfair means to complete their assessment work.

Students need to be taught that they have the responsibility to uphold academic integrity, but also why it is necessary.

This guide explores how teachers can spot AI-written and plagiarised work to ensure that students are learning effectively and staying ethical with their academic practices.

Adding a Detection Tool Into the Assessment Process

Most educational institutions worldwide had to get digitized due to the COVID-19 pandemic. Each uses a dedicated LMS system like Google Classroom or Canvas to keep academics more organized and to work as an online classroom that will keep track of things online.

Many institutions have integrated systems like Turnitin to ensure plagiarism and AI detection are taken care of once students submit.

However, if you feel like they are not a strong enough defense, specifically for AI detection, you can use a separate tool in your assessment process.

Choosing the Best AI Detector

A good AI detector won’t just be able to understand whether a writing is AI-generated when the content has been fully copied, they will be able to detect information that has been paraphrased from automated output.

Detectors will also check the writing for the two primary linguistic metrics like perplexity and burstiness.

Perplexity measures how predictable a word is. Human writing tends to be surprising, irregular, and harder to predict; hence, it has high perplexity. AI writing is pattern-based and highly predictable; therefore, it has low perplexity.

Burstiness measures the variation in sentence length and rhythm throughout a document. Humans write in bursts of inspiration and tend to have a mix of rhythm and sentence length, but AI writing maintains a uniform structure.

So a high-quality AI writing detector should be able to understand whether a piece of writing is AI, and should be used as an initial step before the teacher comes in to comb the writing with their years of experience.

Using Another Tool For Plagiarism

One might think, why would there be a need for a separate plagiarism tool, when an AI detector is already being added.

Well, what if the ideas are not generated but still copied from another person or a research paper, without citation? In that case, using a plagiarism tool is a vital step.

General plagiarism checkers compare your text against a massive database of web pages, books, and academic papers to find matching content.

The tool strips away formatting, punctuation, and any extra spaces, and checks the text against similar texts. It can break the writing into smaller chunks and assign digital fingerprints to these sections to make searching fast and efficient.

The tool runs these chunks through search algorithms to look for matches inside its indexed library sources, which can include public websites, scholarly journals, and internal student paper repositories.

The system uses both lexical analysis, looking for exact word matches or words with minor changes like verb tenses and plurals, and NLP for semantic analysis to detect paraphrasing, synonyms, and similar sentence structures.

Manually Checking Plagiarism and AI

Once the tool has done its trick, it can be straightforward from that point. Generally, for plagiarism, once caught, it is pretty obvious that the academic crime has been committed. But for AI, it’s not that easy.

Many detection tools have a higher rate of false positive, and most institution allow recheck when students appeal for it. To avoid such situations, after a tool has flagged an assignment or essay for AI, you should consider checking manually if you have time. Key red flags for manual check include:

Stylistic Shifts

As a teacher, you have probably read what these students have written before.

When there is a sudden and possibly dramatic change in vocabulary, like they are using more complex words and articulating sentences in a way that sounds more mature, and using a tone that doesn’t match the student’s earlier in-class writing.

So, if they are writing a certain way when attending exams and quizzes, but suddenly turning into Shakespeare when writing their research paper, it is obviously suspicious.

Linguistic Hints

Every teacher has used AI tools, and most know exactly what kind of language these LLMs use. There is a tendency to use specific filler words like “navigate,” “align,” “overall,” and “additionally.”

Em dashes are also a sign, and so are predictable word patterns like “not just X, it’s also Y.”

You can also check for general detection markers like excessively uniform sentence lengths and predictable word choices that lack human rhythm. So, a lack of perplexity and burstiness is still a sign of AI-generated text.

Fabricated Sources

When you ask AI to generate an essay or assignment and add sources for claims, it may not have the exact information it needs to do what the prompt has asked.

In such cases, it can and will make up research or a case study to support a claim it’s making. It can even provide a made-up link to a resource that doesn’t exist.

This is why checking each source and citation is crucial. Students also need to be taught and encouraged to find good sources, like actual literary research and not just the Wikipedia page where anyone can add information.

Final Thoughts

To fight fire with fire, the first step is to check for plagiarized and AI-generated content by using a detection tool, but you cannot leave everything in the hands of such a platform. However, this initial step is vital, so choose tools that have a high accuracy rate.

Some tools come bundled as a platform that offers AI detection, plagiarism detection, and fact-checking, so if you find a trustworthy platform that offers everything, you can opt for it.

Manual checking is also crucial, because even an accurate tool can make mistakes.

When you check manually and find whether the student has actually plagiarized or made a mistake, it opens the opportunity to start a conversation. Use it to teach students to become responsible upholders of academic integrity.