I was at a dinner party this weekend and I sat next to a man whom I had never met before. After talking for a while about the usual stuff like holidays we got round to talking about what we did for a living. I'm a librarian and he it turned out was a lecturer at Birkbeck university. We did digress to talking about the perils of plagiarism and he told me something that I want to share.
A student of his wrote an essay that was put through Turnitin. A standard procedure for the majority of universities these days. This essay came back as 62% plagiarised. When my dinner party acquaintance checked it out it turned out that in reality the student had only plagiarised one source. Why was the statistic so high then? It turned out that the source that the student had chosen to steal from had itself plagiarised from someone else who had also plagiarised from its original source. The chosen source had been plagiarised itself 3 times!
I love this story as it is a perfect reason to tell your students why it is really important to understand where your information is coming from.