How about I offer you another side of these "hard working international students".
Let's see four member team for an accounting assessment with 4 questions. I did drafts for all questions, I did the finalised versions of question 2, 3, intro, conclusion, executive summary, appendices. While I concede this was due to my own poor time management, I stayed up till 5am on Sunday, slept for a couple of hours then didn't sleep at all Monday night. Meanwhile, the two international students were blissfully asleep, although one of them decided to show up at 3am and said something akin to "My PC broke, you finished the assessment?"
My friends doing the same assessment, had an international student who said his phone "broke" and then that "he left it at his friend's house". He apologised for finally contacting them on the day before it was due and begged them to give him a good evaluation and he would take them out to dinner.
There isn't really a way to do "real" research into the matter, apart from first hand experience. Mine has always been quite laughable, oh and what probably puts icing on the cake for this assessment is that for the peer evaluation they both wrote that I did most of the work - no shit when I did basically all of it. The only slight balance here is that the other local student didn't do too much either.