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A BBC investigation has found that prominent YouTube stars are encouraging students to buy essays.

Passing off a custom-made essay as your own is a form of plagiarism known as contract cheating.

It involves a student ordering an essay, usually through a website, for a fee.

But it could also be friends or family members writing an essay on a student's behalf.

Companies offering these sort of services are known as essay mills.

The fee will usually depend on the essay subject, length and deadline.

Image copyright Edubirdie.com

Some essay mills - including EduBirdie - claim that the essays they provide are "100% plagiarism free". But even if the essay you buy doesn't necessarily contain copied material, the act of submitting it as your own is itself a form of plagiarism - according to the Quality Assurance Agency (QAA), which monitors standards in UK higher education.

A student caught doing this could face serious penalties - including expulsion.

EduBirdie says that there is disclaimer on its site which suggested that the work it provided should only be used as a sample or a reference.

What's the scale of contract cheating?

The QAA told Reality Check that it believes contract cheating is on the rise.

In its 2016 report, the agency said leaflets advertising essay services had been handed out on campuses. There were also reports of adverts appearing on university notice boards.

One UK essay writing company boasts that it has helped more than 25,000 students over the past 15 years.

But we don't know how many of those students who used the service went on to submit the essays as their own.

The QAA also referred Reality Check to a 2016 Times investigation. Based on Freedom of Information requests, the newspaper unearthed 50,000 cases of cheating in UK universities over the previous three years.

This works out at 17,000 per year, or 0.7% of students.

The problem with this number, which the QAA acknowledges, is that it includes all forms of cheating - not just contract cheating.

But even if we did know how many students were caught contract cheating, we still wouldn't know how many cases went undetected.

For that we have to rely on survey data, where students are asked if they have ever cheated by submitting an essay written by someone else.

The most recent UK study was carried out in 2012 and found that 29.5% of participants agreed that they had "submitted work taken wholly from an internet source (free or paid) as your own".

Elsewhere, the QAA cites a 2014 study from Saudi Arabia, which found that 22% of students reported having paid someone to write an essay.

Prof Phil Newton, from Swansea University, is an expert on contract cheating. He says that with surveys of this nature, there's always a likelihood that respondents may not give accurate answers - especially if they are owning up to deviant behaviour.

So, we have to treat survey data with a degree of scepticism.

Are these services legal?

At the moment there's nothing, legally speaking, to stop websites selling essays.

In fact many websites contain disclaimers that say students shouldn't pass off the essays as their own and that they should only be used as study aids.

That said, in March 2018, the Advertising Standards Agency (ASA) upheld a complaint about claims appearing on a UK essay mill website.

The ASA said the website gave the misleading impression that "consumers would be able to submit purchased essays as their own without repercussion".

But even if legislation was brought in, the QAA says it is unlikely to solve the problem.

It says many of these websites are offshore and even if they were closed down they can easily re-emerge.

So what can be done about it?

Contract cheating can be very difficult to spot. As the essays are bespoke they're unlikely to be picked up by software which some universities use to detect plagiarism.

Last October, guidance was issued to institutions on how to deal with contract cheating.

Have fewer assessments by essays

Block essay writing websites from IT systems

Get familiar with student writing styles and try to spot any changes

Have clear procedures to report suspected cheating

Support struggling students with their writing skills

Why do students do it?

There are many reasons - it could be as simple as laziness or a lack of confidence in writing ability.

In April, Prof Newton, along with colleagues, published a study into contract cheating in Australia.

The study focused on students who had asked either friends or family members to write essays on their behalf.

The researchers found that were three factors which increased the likelihood of contract cheating.

Students who spoke a language other than English

A dissatisfaction with their learning environment

Where students perceived there were opportunities to cheat

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