Students' illicit access to answers for online homework systems I teach physics. Back in the 90's, people teaching freshman physics were pioneers in creating open-source systems such as LON-CAPA for checking students' homework answers. Today the use of open-source or home-grown systems has become uncommon and has largely been replaced by the use of MasteringPhysics, a product of Pearson which functions both as a revenue stream for the publisher (students pay per semester) and as a way of killing off used textbook sales. During this same period of time, we've seen the advent of web sites such as Chegg that sell students access to answers to homework. Physics homework seems to be the killer app for Chegg. If you read about Chegg et al. in the media (example), physics homework seems to be a dominating presence.

In a 2010 paper, Palazzo et al. study students' cheating in MasteringPhysics using an ingenious technique applied to their classes at MIT. They make the following claim:


  Our survey shows that copying written homework is more
  prevalent than copying electronic homework. [...] This may be because the most common self-reported
  mechanisms for copying written homework on our survey,
  “copying a borrowed assignment” (58% of survey responses)
  and “finding the solution online” (34%, often using the MIT
  Open Courseware site), are not available avenues for the
  electronic homework.1 Furthermore, online students who are
  stuck on a problem or unsure whether their solution is correct benefit from the feedback and hints available, reducing
  the need to “borrow” others’ assignments.
  [footnote 1] Pearson
   regularly searches for posted solutions to its Mastering-
  Physics problems and requests that they be removed from the web.


Question: Does anyone have any reliable information about whether it's true that Pearson is (or still is) successful at this?

It seems unlikely to me, given what I've read in the media and what I've heard from students. However, I'm not in a great position to evaluate this for myself. In my classes, I use an open-source system rather than MasteringPhysics, and I also haven't paid for access to Chegg, so although I can search for the text of a problem in a printed book and see it pop up in Chegg, I can't see what the solution is. I also don't have access to the text of the problems in MasteringPhysics, so I can't search on the text of those problems. My impression is that most of the problems in MasteringPhysics are actually just minor variations on the problems in the printed text, but I don't actually know for sure. I wonder whether this statement by Palazzo is out of date, or was perhaps unrealistic even in 2010 and influenced by assurances from Pearson's sales reps. From what I can tell, Chegg's business model is designed to make it practically impossible for a textbook publisher to do what Palazzo claims Pearson does. It seems like it would be an endless game of whack-a-mole.

Palazzo et al., "Patterns, correlates, and reduction of homework copying," Phys. Rev. ST Phys. Educ. Res. 6, 010104 (open access)
I talked to a group of students about this, with the understanding that of course they would have no personal knowledge of it, but ... er... they might know someone who had experience with Chegg.

Before I had even finished explaining the question, some of them were already laughing. They say that 100% of MasteringPhysics questions are on Chegg, including both the conceptual questions and the quantitative ones.