I teach math classes online, and I'm curious if anyone else has had success with some of these plagiarism detection tools in a math environment. My particular issue is with "show your work/explain your process" problems where students are going through some kind of complicated story problem and explaining how they modeled and solved it.
I generally have no trouble catching students myself (my main case this year involved students who were both clearly visible in the Revision History of one of the Google Docs, where Student B went into Student A's Google Doc after Student A had submitted it and poked around a bit before copying the whole thing to his own Google Doc and turning it in late), but my issue is the time delay between when they turn in their work and when I grade it. My general policy is to grade things that were turned in on time in a timely fashion and things turned in late whenever I happen to have some extra time but before I submit quarter or semester grades. (I let students submit assignments up to 2 weeks late in most cases - this means I don't have to spend much time playing Excuse Police with students who are mostly on track but a day late here or there. It also means that if a student is contacting me asking me to re-open an older assignment because they ran out of time, I have a much better "case" for saying no since it was due more than two weeks ago so they already had a substantial amount slack baked in.)
(I don't like to grade things as they come in individually because I use a annotated key and cross-compare so that similar mistakes or omissions get similar feedback and similar scores. Getting back in my my "grading mindset" for that particular assignment takes some time so I want to go through and grade each assignment for different students as few times as possible.)
However, this set of policies mean that the time I'm mostly likely to discover wholesale copying (or clumsy word-changing copying) is right before grades are due and not very near the time something was turned in. (Students who copy work are likely to be turning in things late as well.) This means I generally don't have time to have a parent conference, bring admin in, have the student sit down and do the assignment in a supervised environment, or any of the things I'd really like to do.
What I'd like is a good originality-checker that understands that some things should be the same (students are likely to post a very similar series of algebraic steps for some problems, and copy and paste the assignment directions into the file they submit), but can give me some kind of warning that I might want to take a gander at a particular late submission as soon as it was turned in so I can start the discussion about doing your own work when the issue is fresh.
In my case, I'd need it to work with URL submissions of Google Docs, since that's what the majority of my assignments are. I'd also want it to flag images within those Docs that are from the internet rather than student-created (some students resist learning how to use a program like Desmos or GeoGebra to create graphs and then include them as screen shots, and instead try to Google Image Search for existing graphs that "might work" for the assignment).