Is editing the mc-stan documentation legal under the cc-by-nd clause?

According to @Bob_Carpenter the contributions to the mc-stan documentation are licensed under the Creative Commons CC-BY-ND license (Mc-stan documentation license precludes easy reuse - #14 by Bob_Carpenter), and the contributors are the copyright holders issuing the license. The “No Derivatives” clause in the license prohibits derivative works. The Creative Commons defines a derivative work as “…a work based on one or more pre-existing works.” (Frequently Asked Questions - Creative Commons).

When one user submits to the documentation an edited version of a document first written by another user, is that not a derivative work? If so, then is hosting the derived work not a violation of the CC-BY-ND license?

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When one user submits to the documentation an edited version of a document first written by another user, is that not a derivative work?


then is hosting the derived work not a violation of the CC-BY-ND license?

See the section 2.a.4 it’s fine to reformat it. You can make changes for the purpose of reformatting. You just can’t change the words themselves

Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures. For purposes of this Public License, simply making modifications authorized by this Section 2(a)(4) 2 never produces Adapted Material

Thanks for the response Steve. I think there might be a misunderstanding here. My question here is not about reformatting. My question is about what happens when a user changes the meaning of content that another user has written. An example:

User A creates a file. User B then comes along and makes changes to that file that change the meaning of what user A had written by rewriting passages and adding extra explanations and examples. Why is user B not creating a derivative of work created by user A (under US law, say).

Another example:
I pulled the commit from a recent PR. I do not mean to single anybody out, but I think a concrete example might help illustrate things. In this commit, a user has inserted new content within content written by other users: edited zero inflation and hurdle section by avehtari · Pull Request #611 · stan-dev/docs · GitHub

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I’m commenting just this example. The copyright owner can keep editing CC-BY-ND work after it has been made public. The copyright owner of that documentation is Stan Development Team, I’m part of Stan development team, and thus no problem there. If someone not part of Stan Development Team made a PR, that can be considered as suggestion and the PR message contains explicit statement that the PR can be used by Stan Development Team for the documentation with CC-BY-ND license, and then it’s again the copyright holder making the actual edit, so no problem there.

This is also the official Github policy:

Thank you everyone for engaging with me on this. I agree with what @rok_cesnovar said. Responding to some of the points @avehtari makes:

The copyright owner can keep editing CC-BY-ND work after it has been made public.

Correct. The copyright owner can always edit their own work and issue a new CC-BY-ND license for it when they are done. This is not what I am concerned about.

The copyright owner of that documentation is Stan Development Team,

This is news to me. According to @Bob_Carpenter, the contributors, not any team they might be a part of, are the copyright owners (See initial post for link). Therefore, the contributors themselves are the only entities that can issue a license for their work.

My concern is not with whether new contributions are properly consented; that looks fine to me. My problem is that when @avehtari 's commit was accepted, nobody asked Mitzi Morris whether Mitzi was ok with @avehtari creating an adaptation of Mitzi’s work by adding a bunch of new text in the middle of Mitzi’s work.

Here is an example of some of the git blame for the commit in question that I hope illustrates the point:


Here are some excerpts from the Creative Commons FAQ (Frequently Asked Questions - Creative Commons) that I think may be relevant:

Can I reuse an excerpt of a larger work that is licensed with the NoDerivs restriction?

There are exceptions to that general rule, however, when the excerpts are combined with other material in a way that creates some new version of the original from which the excerpt is taken. For example, if a portion of a song was used as part of a new song, that may rise to the level of creating an adaptation of the original song, even though only a portion of it was used and even if that portion was used as-is.

What is an adaptation?

In order for an adaptation to be protected by copyright, most national laws require the creator of the adaptation to add original expression to the pre-existing work. However, there is no international standard for originality, and the definition differs depending on the jurisdiction. Civil law jurisdictions (such as Germany and France) tend to require that the work contain an imprint of the adapter’s personality. Common law jurisdictions (such as the U.S. or Canada), on the other hand, tend to have a lower threshold for originality, requiring only a minimal level of creativity and “independent conception.” Some countries approach originality completely differently. For example, Brazil’s copyright code protects all works of the mind that do not fall within the list of works that are expressly defined in the statue as “unprotected works.” Consult your jurisdiction’s copyright law for more information.

I love the mc-stan documentation. But the way I see it, any of the earlier contributors (or their heirs?) could sue to stop the publication of the documentation because the ND clause does not allow adaptations to be made. Surely not all changes submitted to the mc-stan documentation are adaptations under most jurisdictions, but the only way to find out may be to go to court. Why would we as a community want to put ourselves in that position?

Now, I am not trying to just point out flaws, I also want to help. If the community decides that we need to get everyone to issue their work under a new license (CC-BY anyone?), then I volunteer to help make it so.

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That was my understanding as well. Most contributions are from Stan Development Team members but not all. The pull request template only says

By submitting this pull request, the copyright holder is agreeing to license the submitted work
under the following licenses:

and to me it doesn’t look like that transfers copyright or gives the Stan Development Team any special permission to create derivatives.

The copyright notice on the published documentation page says

This book is copyright 2011–2022, Stan Development Team and their assignees. The text content is distributed under the CC BY-ND 4.0 license. The user’s guide R and Stan programs are distributed under the BSD 3-clause license.

I suppose “and their assignees” covers everyone who has submitted pull request to the docs repo but is not part of the Team.

I think we are getting closer to the issue I am trying to raise. In order for the Stan dev team to be able to issue new licenses for existing work, the team would need to be the copyright holder or possess a licence that allows the issuance of new cc-by-nd licenses for existing work. The cc-by-nd license itself does not allow this (for obvious reasons, i hope?).

Are Stan development team members employees of some legal entity under US law by any chance? Under US law an employer usually owns the copyright to work performed by an employee for the employer. If not, then perhaps the copyright notice for the book should more accurately read

This book is copyright 2011–2022, members of the Stan Development Team

That’s what the front matter of the document indicates (with big font).

I comment again just this specific case. Mitzi was asked to review the specific PR you linked. You can still see this in the PR.

Great that you are thinking this also beyond the specific example.

The copyright owner of that documentation is Stan Development Team,

That’s what the front matter of the document indicates (with big font).

I think now we are venturing outside of open source code conventions. Just because a document asserts something does not make it true. I think a future heir of Mitzi might argue convincingly that Mitzi was asked in their PR to provide a CC-BY-ND license for the work and not to transfer copyright to some non-legal entity called the Stan Development Team.

nobody asked Mitzi Morris whether Mitzi was ok

I comment again just this specific case. Mitzi was asked to review the specific PR you linked. You can still see this in the PR.

That is fantastic! But I think it also illustrates the problems inherent to having every copyright holder review a PR that affects their prior work. What if Mitzi gets hit by a bus? Do we then have to get the Mitzi estate to approve PRs? Or does development on the stan documentation simply stop due to unresolved legal issues?

If I go back to the PR and pull out all the contributors who’s work has been adapted, will I find that all of them approved of the PR?

Does approving of the PR really mean that Mitzi is issuing a new CC-BY-ND license for the adapted work? I don’t see that spelled out anywhere, and it is not common practice in the open source community. These questions usually don’t arise in documents where users edit each others’ work (for example wikipedia) because those documents are licensed under a license that allows derivative work.

Incidentally, I have been searching for a major wiki running under the CC-BY-ND license and have not found one yet. I would be very interested to see such a specimen.

tagging @SGB since I don’t think they’ve been formally tagged here.

Mitzi is honored to have Aki Vehtari edit her work. ;-)

more seriously, thank you for bringing this to the attention of the SGB.

the Stan project’s use of the license and practices around edits and PRs is standard across OSS projects. perhaps some lawyers and judges could find conflicts between existing copyright law and our use and interpretation of the CC-by-ND clause. the arguments in favor of using and continuing to use this license are:

  • the work isn’t a derivitive of itself, it’s a single collaboratively edited thing
  • “Stan Development Team” is an umbrella term for all contributors
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Mitzi! I am honored to have you drop in on this thread.

Lots of big picture arguments from Mitzi. Let’s see if I can drag things back into the details :)

Let me address two of Mitzi’s claims:

Claim 1: We use OSS practices, so our use of the CC-BY-ND license for documentation is on a sustainable legal footing.

If we were discussing an OSS license, then I would agree. However, CC-BY-ND is not an OSS license because it is not for software and it is neither OSI nor approved. But perhaps we are fine because CC-BY-ND is commonly used in OSS projects for documentation? I am not aware of a major collaborative OSS project that uses the CC-BY-ND license for documentation, so I did some research:

I checked wikipedia’s list of major works using a Creative Commons license. I found a few single author books that use an ND clause. None of the works listed under the following sections use an ND clause: Educational Resources; Games; Knowledge, Research and Science; Technology, blueprints and recipes; Websites (except for two anomalies that I think are errors). Only one of the works listed under Video Games uses an ND clause. That game was released as abandonware under the ND clause when the studio owning the rights to the game went out of business.

But we are discussing OSS projects, so I looked into some big ones. The Python developers created the Python Software Foundation in order to “own Python-related intellectual property”. The python documentation is licensed under the Zero Clause BSD License. The R core team created the R foundation to “Hold and administer the copyright of R software and documentation”. The R manual R-intro is released under a BSD-like license that allows derivative works. “The Rust Programming Language” book is hosted on github just like the stan docs and uses the MIT and Apache2 licenses for contributions.

But this investigation would not be complete without the answer to the question: What Would Hadley Do? Hadley Wickham is about to publish the second edition of a book called R for Data Science. The open-source website is available under the CC-BY-ND3.0 license. He asks contributors making substantial contributions to the book/website to assign their copyright to Hadley Wickham so that he can publish his book.

I am happy to be proven wrong, but to my eyes, the CC-BY-ND license is an exotic choice for the documentation of a collaborative OSS project, with the notable exception of Hadley’s book, although I think Hadley may be aware of the same issues that we are discussing here because he asks for a transfer of copyright upon contribution. I therefore don’t see how the stan community’s choice of licenses is “standard across OSS projects”.

Claim 2: The work is not a derivative of itself, it is a single collaboratively edited thing

While in our hearts we all know this to be true, legally, this does not match anything I have ever read about copyright. It also does not match my reading of the stan docs contributor agreement. When a group of copyright holders gets together to publish something, an academic article say, then all copyright holders need to consent to the publication of their joint work by issuing a license or transferring their copyright. Absent a transfer of copyright to the publisher, this consent needs to be obtained every time a revision of that work is published. However, with code that is publicly hosted on github, every commit is a revision of the publication. Absent a permissive license, every copyright holder needs to consent to the hosting of every commit publicly available on github. The CC-BY-ND license does not avoid this issue because it can only be issued for currently existing work. The ND clause even explicitly witholds consent for future work derived from the current work. I suppose reconsenting everyone could be done while the copyright holders are still able and willing to consent, but there is the Mitzi-getting-hit-by-a-bus-problem.

This issue could be avoided if we took the route that Python, R and Hadley took by asking contributors to transfer their copyright to a legal entity such as a non-profit or Hadley Wickham. The entity could then choose to make the documentation available under any license that it chooses. Alternatively we could take the route of the Rust book and allow all contributions to be turned into derivative works through a permissive license.

Please don’t let the stan docs become abandonware ;)

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I would say it’s a revision of the same work.

Is there a legal precedent you’re worried about?

Not quite. You can see from the closed pull requests in the docs repo that the contributor declares who owns the copyright.

I did a quick search as to whether a new version counts as a derivative work, and the answer seems to be yes. So maybe we do have a legal issue here.

The only reason we haven’t changed the license to just plain CC-BY is because of the number of contributors. I’d personally rather just have it go out CC-BY.

I’m worried that there really isn’t a legal precedent (but this is something lawyers specialize in; I am not a lawyer). The creative Commons case database only has a single case featuring an ND clause (relating to the reuse of music in an advertisement).

The Stan community’s use of the license for documentation also appears to be unprecedented when I take a look at the details of how we apply it.

I had a quick look at the insights page on GitHub, and there appear to be around 30-50 contributors depending on where you draw the line for a substantial contribution. Contacting this number of contributors for licensing is regularly done for major academic articles. As I’ve said, I would be happy to lead this effort. Here are the steps we could take to switch over:

  1. Change the license used for PRs to CC-BY immediately.
  2. Create a new document inside the repo that describes why we need all contributors to relicense any contributions made before 2023-02-16 under the CC-BY license. Then users can add their name to the document through a PR.
  3. Any contributions that cannot be relicensed in this way need to be removed from the git history and somebody else would need to be found to write a new entry for any contributions that are lost in this way.
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