What tool or process can I use to see revisions on papers I am grading? Like many professors, I ask for drafts of papers of more than a few pages (1500+ words). I provide comments focused on content. (I might make occasional corrections to grammar or word choice--particularly if a term of art is misused--but since I am not teaching writing-focused courses, would be more likely to refer a paper with consistently poor grammar, misspellings, etc., to the campus writing center.)

The problem comes when I am grading revisions. Occasionally a student will overlook some of the recommended changes. Maybe they ran out of time, maybe they disagree with the suggestion, maybe they're just surly. I don't know. But sometimes when looking at revisions, I will want to know what has changed in the text, and will end up having to look and awkwardly compare their draft submission.

My question is what tool or process can I use to see revisions as I am grading the final submission?

I will briefly share some experiences and biases:


Microsoft Word with Track Changes: I'll entertain arguments that this is the way to go, but I have two issues which I'll make clear up front. I have tried this, and when students get my revisions, they will accept my in-line revisions, but it doesn't make them think about what they are writing. Of course, they could still make changes based on margin comments. Another issue is that I am using Linux. Doing track changes in LibreOffice does seem to work, but I am not confident that this won't lead to errors.
Crocdoc (tool built into LMSes like Canvas and Blackboard): I love Crocdoc. The student can upload in MSWord or PDF and you can view and edit in the browser. You can do copyediting marks on the page, but unlike MSWord Track Changes, the students have to make the proposed change themselves, rather than just accepting your edits. Margin comments and global (assignment) comments are also supported. The problem is that you can't simultaneously view versions without actually downloading the files.
Version control system (e.g. GitHub): Might be able to get away with this in a technical program. Would be happy to hear people's experiences if anyone has used this for grading papers as opposed to coding projects.
Plain text/markdown: Even without using a version control system, I could use diff tools to view revisions on my local machine.
Use strikethrough and bold in the document: Would be similar to my experience of journal article revisions. Main problem is sometimes drafts are very preliminary, in which case the final "revisions" will be almost an entirely different paper. Maybe don't use in that case?
Google Docs: I've tried this. It wasn't bad, but without typical LMS tools I had a huge problem keeping submissions organized (in terms of what I've already reviewed, when student edits constitute a submitted revision). This would work better for supervising a thesis or independent study, but was tough with a class of 20. Also, I was annoyed by constant emails as student marked my comments as "Resolved".


These are just ideas. Feel free to expand or ignore, and please suggest things I haven't thought of.
At my university, our agreement with Google is designed to make sure the content is hosted in the US so that FERPA-covered materials can be posted to it (I think. I know it's true for Gmail). This includes shared Google Docs which would have the full change history. If that works for you, then you could easily go with that. I'd check with your university-wide, central IT department (if you have one) to see if this option is available to you, too.