While grading papers for my two Shakespeare classes, I made a distressing discovery: 25% of them were on the same topic. They weren't just responding to the same prompt, but applying that prompt to the same rather narrow subtopic--a subtopic that was not among the handful I'd suggested.
You know what came next: I Googled it, and discovered that there are approximately a million hits for this topic. It comes up in every discussion of the relevant play and there are dozens of free essays available on the web.
It also happens to be a stupid topic. It's simultaneously obvious and really difficult to do well; if anyone had run it by me, I'd have warned him off. But because it's so obvious, and suggests only a couple of possible lines of argumentation, it's impossible to tell whether any given essay is borrowing ideas from the internet, recapitulating a half-remembered discussion from high school, or doing original (if uninspired) work. Nothing is directly plagiarized: I put in the long hours ascertaining that. But other than writing a motherfucking airtight prompt for next time, what's a girl to do?
I did the only thing I felt I could: I announced to both classes that I believed a number of their essays--giving no specifics--contained ideas derived from uncited sources. I emphasized that it was okay to get information or inspiration from elsewhere, if they were otherwise doing original work, but that they absolutely needed to credit all sources. I told them I would give them 48 hours to get me a new bibliography (and, if necessary, a new copy of their paper with any previously-omitted citations), but that otherwise their grades would be affected.
I should have been able to predict the results.
My students examined their consciences, and at least dozen emailed me confessions. One acknowledged that he hadn't cited a source for the date of the battle of Actium. Another revealed that her decision to write about women in Coriolanus had been inspired by a discussion about gender roles in her Russian Novel class--and she apologized for not crediting that professor. They were, all of them, so very sorry.
I guess guilt-tripping is never a waste.