Plagiarism: how to spot it and what to do about it

Last updated 15 November 2022

Whether it’s done accidentally, unthinkingly or with malice aforethought, plagiarism is a perennial problem in publishing. Sometimes it might result from an author’s genuine ignorance of the rules and conventions surrounding the reproduction of others’ work; sometimes it might be a shortcut (for example, if an author is commissioned to write in a language other than their own and struggles to formulate their own words); and sometimes it is simply the deliberate theft of another author’s words.

Whatever the case, it is deemed ethically unacceptable and may lead to major legal and reputational damage for the plagiariser and the publisher.

Definition of plagiarism

Plagiarism is the reproduction without credit or permission of material (text or images) previously published elsewhere in such a way that the material appears to be one’s own. It applies to material of any length, even a few words, and it encompasses ideas as well as actual words.

Crucially, this definition includes ‘self-plagiarism’, or the reproduction of one’s own material.

It’s commonly said that it’s unlikely any two authors will write the same seven words in exactly the same order. So, if a sequence of seven words written by your author appears in another publication, it’s a strong clue that you might have a case of plagiarism on your hands.

How to avoid plagiarism

The basic rule is that, if an author wants to use text that has previously been published (even in a more informal format such as a blog post), it must be put within quote marks and credit must be given to the original author. Credit usually takes the form of a citation and reference (in a book or article) or perhaps a hyperlink to the original material (in online content).

Additionally, it is not acceptable to re-use text but change a few words here and there to make it different from the original.

If you want to cite or refer to your own material, it’s standard practice (particularly in academic writing) to quote yourself just as you would any other author. Alternatively, if you want to avoid doing that, rewrite the material afresh.

Another point to consider is that, even when text has been correctly placed in quote marks and credited to its original author, it may still be necessary to seek permission from the copyright holder. This is a separate issue. Gillian Davies’ book Copyright Law for Writers, Editors and Publishers (A & C Black, 2011) is a useful guide to the issues surrounding copyright (and has some helpful content on plagiarism too).

Is it the editor’s responsibility to find plagiarism?

In short, no.

Unless specifically contracted otherwise and provided with appropriate tools to do so, a copy-editor cannot generally be expected to identify plagiarism. It is often invisible and, short of laboriously running an entire book through a plagiarism checker (which could take many hours as they usually have word limits), it can be impossible to pick it out.

However, there are certain clues editors can look for to help them identify plagiarism. When they spot it, they should report it to their client immediately (or discuss it with the author, if the author is also the client).

How to spot plagiarism

All of the issues below can be and almost always are innocuous authorial errors that have nothing to do with plagiarism. However, particularly prominent or repeated issues, or several of these issues in combination, might mean it’s worth popping a sentence or two into Google and seeing what results come up.

From the prosaic to the sublime (or vice versa)

A sure clue is when an author’s writing style suddenly changes mid-way through an article. This might be a switch in tone (such as informal to formal), or it might be a jump from rather messy English to a more polished style. There are all sorts of possibilities, and they can be subtle. However, they can be spotted if the editor is paying attention. My post on authorial voice might give you some ideas on what to look out for.

Ambiguous nationality

Different languages and regions of the world have different spelling and punctuation conventions. If your author starts out by writing consistently in UK-style English and suddenly switches to US style (for example), it might be a sign part of the text has been copied from elsewhere.

Contrary referencing

If an author isn’t too hot on the subtleties of constructing reference lists, a paper will often quite naturally contain a variety of referencing styles. However, consistent inconsistencies – where, rather than a hodgepodge of styles, there are discrete groups of references each with their own perfectly implemented style – may be a sign to take a closer look.

Disjunctions in content

Paragraphs that appear to have been stuck together with little continuity of argument might contain content that’s been ‘borrowed’ from elsewhere.

Erratic styles

In addition to editing the actual text, editors are often asked to standardise the styles in a piece of work (a ‘style’ in MS Word is a set of characteristics, such as font, size and colour, that is applied to text). Sometimes, the process of applying styles reveals that what initially appeared to be all one underlying style of text actually contains multiple styles. This may be a sign that text has been copy-pasted from another digital source (bringing with it the original source’s style).

Plagiarism checkers and tools

If I suspect something dodgy is going on in a document, I always start by simply pasting a sentence or two into Google. I put quotes around the text so that Google looks for that exact string of words.

Alternatively, when I need to check a longer body of text all at once, a tool I’ve found useful is Quetext. Quetext is free to use and claims to compare text with ‘the entire internet and other databases’. It will check up to 10,000 characters at once and then displays instances of possible plagiarism. However, there is a whole host of other tools that can be used, all with slightly different focuses and designs. (And, in case you were wondering, I am not in any way affiliated with Quetext.)

If I suspect plagiarism, I tend to use one or both of these methods to perform quick-and-dirty checks. If I find anything, I then send the material back to my client for them to investigate further, or, if the author is my client, I tactfully broach the subject with them.

A word of caution

One final – and vital – point is that editors and proofreaders should always be extremely careful raising issues surrounding plagiarism. Especially in academia, it is taken very seriously, and it can affect authors’ whole careers. Even when you have a case of plagiarism so obvious the author may as well have tied a red bow around it, raise the issue with great care. The author may be genuinely ignorant that what they have done is not acceptable (I have identified several instances of plagiarism where this was the case).

I start by picking the most appropriate person to contact (not the author, unless the author is also the client) and asking them to verify my suspicions. Never fire off a round robin to the whole project team (and the author). Doing so may only lead to unnecessary embarrassment for the author (or you, if your suspicions turn out to be incorrect – for example, if the ‘plagiarism’ is an authorised reproduction but your contact forgot to let you know about it).

I’ve seen my fair share of problems arising from both unwitting and more malicious plagiarism: projects delayed, time wasted, authors upset, even entire chapters pulled. Ideally all authors would know about and avoid such issues right from the beginning of their writing process. However, failing this unlikely eventuality, eagle-eyed editors can save their clients and authors much hassle and heartache by learning the signs of plagiarism and reporting it whenever they find it.

What other methods have you found to help you spot plagiarism? Do you have any horror stories to share, or any ‘whoop!’ moments where you saved a client from disaster? Let us know in the comments!

About Hazel Bird

Hazel delivers editorial services that empower non-profits, charities, businesses and authors to confidently share their expertise and impact. An editor since 2009, she aims to see the big picture while pinpointing every detail. She has been described as ‘superhuman’ and a ‘secret weapon', but until Tony Stark comes calling she's dedicating her superpowers to text-based endeavours.


  1. Dorothy on 25 March 2017 at 09:19

    Grammarly checks plagiarism. Lots of false positives, but those are easy to spot … and the tool does flag the problems. I trust Grammarly.

  2. Joanna on 25 March 2017 at 17:43

    I recently had a case where I suspected steps had been taken to disguise plagiarism. The client (not the author) assured me that it was not the case, but how else do you explain the phrase “the alternative celebration” in a piece about conflict resolution, where “the other party” makes perfect sense?

    • Hazel Bird on 25 March 2017 at 18:24

      Hi Joanna – Wow, yes, that seems a pretty clear-cut case! Thanks for bringing up the topic of synonyms being used to (attempt to) disguise plagiarism. Not something I come across much in my work but it can definitely be a sign something dodgy is going on, especially in student essays.

  3. Averill Buchanan on 26 March 2017 at 13:12

    This is a really useful post, Hazel. Thank you!

    Another tell-tale sign, and you do touch on it in your post, is the invisibles in Word. If I see non-breaking spaces, manual line breaks, hidden hyperlinks and/or optional hyphens, it usually indicates that the text has been copied from a browser.

    • Hazel Bird on 26 March 2017 at 13:19

      Thanks, Averill 🙂 It’s great to have others’ ideas here to add to my suggestions.

  4. Tony Hazzard on 27 March 2017 at 21:50

    Now try delving into the murky world of songwriting…. 😉

  5. Rona on 28 March 2017 at 11:25

    I work for an academic journal and we recently had a case of what seemed like blatant plagiarism. We run all papers through iThenticate and initially the score was very low, so no problem. Several months passed before the paper was accepted and editing commenced. When checking the author’s reference list I wanted to verify a ref source so googled that ref. What came up in the search was a link to a paper with exactly the same title and author as the one I was editing! Long story short, it turns out the poor author had previously submitted the paper to what turned out to be a predatory journal. Not liking their processes, she withdrew the paper – she had signed nothing and paid nothing – and they published it anyway.

    • Hazel Bird on 28 March 2017 at 11:28

      What an awful story, Rona! And definitely a cautionary tale for anybody who too quickly jumps to attack the author when an apparent case of plagiarism arises.

  6. Robert Frank on 3 April 2017 at 08:39

    These are actually some tips I’ve never considered including the style change from US to British English. Good thinking! I had an issue a few months back where I found a website was routinely scraping content from my blog. I’ve been using Copyleaks ever since and it notifies me immediately if duplicate text of my own is being used elsewhere. Not letting my Google rankings get messed up again!

  7. […] Plagiarism: how to spot it and what to do about it by Hazel Bird […]

Leave a Reply Cancel Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.