CUNY Academic Commons

I also recreated the issue here so it may not be user dependent (if that was a possibility...)

https://via.hypothes.is/https://classtestbmcc.commons.gc.cuny.edu/files/2019/09/Chapter-51.pdf

Thanks Boone. I figured this might be a hypothesis issue, thanks for confirming. I will reach out them and circle back with any relevant info.

The hypothesis issue was document "fingerprinting". If docs have the same fingerprint the annotations will appear across all docs with that fingerprint. I am working with the professor who experienced this issue to create new doc fingerprints (Solution #2 below). This will be helpful to know in the future as more faculty may use the same pdf across multiple courses.

More below from the Hypothesis folks.

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Every PDF has what's called a "fingerprint", and Hypothesis uses this fingerprint to tell PDFs apart. This means that if I emailed you a PDF and we both saved different copies to our hard drives, we'd still see each other's annotations in our copy of the PDF.

Looking at both the longer and shorter PDFs you sent me, it seems that they both use the same fingerprint, so Hypothesis treats them as the same document. You can read how to check PDF fingerprints here. https://web.hypothes.is/help/how-i-do-i-check-and-make-sure-my-pdfs-have-different-fingerprints/

I have two solutions that I think will help: using Hypothesis groups and making new PDF with a different fingerprint. I'll walk you through both, but of the two, the former is the better option.

1) Using groups
The easiest way to use groups would be to install Hypothesis' LMS app at your institution. Every course will get its own group, and the "Public" group option disappears, so students won't mistakenly put their annotations into the wrong group.

Outside of the LMS app, your professor can also create a private group for their class and then invite their students into it. They can make as many groups as they like; the best practice would probably be to make one for each class separately (so Fall '19, Spring '20, etc.). When students visit the PDF using the links in your email, they need to make sure they post in the appropriate group.

2) Change the PDF fingerprint when creating a new copy
Here's an article on changing a PDFs fingerprint. Note that this is a workaround; users have reported that this seems to work once or twice, and then subsequent PDFs will no longer get the new fingerprints. I have been able to create as many new fingerprints as I need using Preview on a Mac (instead of Google Chrome, as directed by the linked article); I have yet to find a consistent solution for Windows.
https://web.hypothes.is/help/how-to-save-copy-of-pdf-with-a-different-fingerprint/

Thanks for sharing this, Laurie! Good to know about the fingerprinting.

Private groups and LMS integration won't work for the Commons at this time, as I think our recent call with them made clear. Might be something we pursue in the future.

For the time being, once we've determined which technique works reliably for re-fingerprinting PDFs, we may want to add it to any Hypothesis documentation we might maintain.