How to measure legal openness: The role of public domain status and open licensing

Hi all,

I’m a researcher with Open Knowledge International and currently working with @Mor on the Global Open Data Index.

We were discussing the role of open licensing in our current measurements of openness and the potential bias towards jurisdictions with copyright law. The Open Definition 2.1 states that “work must be in the public domain or provided under an open license” and another article signed by Joshua Tauberer et al. states that “open licensing presumes copyright protection”.

  • I hope this question is not obvious, but am I right, that the Open Definition 2.1 also defines government data as open data if they are not openly licensed but in public domain, i.e. “licence-free” (given that the other criteria of the Open Definition are met)?
  • Would you agree that applying an open licence (except from CC0) could also decrease the openness of government data that are in the public domain by default (through the application of attribution, share-alike and other conditions of use)? Would you agree that there is a potential conflict between public domain status and the application of open licences (and do you know of cases where this happened)?
  • In order to acknowledge the existence of non-licensed open government data in the public domain, would you agree that global measurements like the Global Open Data Index should measure whether government data are in the public domain by default and whether they are openly licensed?

Since I’m not a legal expert I would be very happy if you could help me clarifying these points.

All the best,


No, not really. You can’t “downgrade” the status of a Public Domain work. When a work is in Public Domain, it stays in Public Domain. You can, of course, create a derived work and license it with something else other than PD/CC0. And if someone does that (picks a work in public domain, creates a derivative work, licenses it with a more restrictive - even if open - license), while it is potentially restricting the free use of their resulting work more than they could, it is in no way restricting the use of the original work – it stays in the Public Domain.

If (and I am not sure about the scope of your question) you are meaning “new data starts being published as something else instead of Public Domain”, then yes, that would be - in my prespective - an huge step backwards. However, if the scope on where this is being thought of is considering an Open Licence, as defined in the Open Definition, as “good”, maybe there’s no preference there for some Open Licenses in detriment of others…

Thank you for clarifying this, @marado!

I was partly wondering because I assumed that some governments might license data (with good intentions) that is already published in public domain and thought that this might restrict the use of data or at least cause more confusion for users (given that the terms of a licence might contradict the public domain status). But this seems clear now.

Also, relating to another thread in this forum, I’m wondering 1) if measurements like the Global Open Data Index should acknowledge and better highlight public domain status and give less emphasis to open licensing per se, 2) how we can evaluate and validate the “open status” of gov data in different countries even if it is not stated as such through an open licence or a disclaimer (e.g. by linking to copyright laws or statements of public domain status, terms of use, or similar texts).

I’m trying to disentangle open licensing from public domain status in my head, and to clarify whether we should, and how we can evaluate more coherently the public domain status if open licences are absent (be it through disclaimers or other texts).

Maybe you or someone else in this forum has an opinion to this (since it didn’t seem to be fully clarified in the thread I linked above)?

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I agree that you can’t downgrade public domain by adding another license. But double-licensing can create confusion.
I also think that if a country does publish everything under public domain, then specific licenses are not that important, as public domain can be seen as the catch-all license.
But, if the public domain license is not explicit in the open data portal, how can the public find out? And in this case, should this be considered to be less open?

Also, I wouldn’t say that a license that requires “share alike” is less open, on the contrary, I think this creates more open data by requiring derivative works to be openly licensed as well. The problem being that this could discourage some users of this information that would lack incentive to improve the information if they have to share it.

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Wikimedia Commons does this extensively. See Category:Public domain by government - Wikimedia Commons for government-work-specific statuses (BTW if anyone else is reading this in California, ours is threatened). It might be useful to use/link to those categories or their wikidata item identifiers. Keeping track of all the different possibly open statuses in the world is a huge job, may as well collaborate with the community most actively doing the work.

You can try and craft/claim your open license creates a contractual obligation.

But unless the law is extremely clear about what is not subject to copyright or similar, and that this applies worldwide, I tend to think adding an open license, even one with conditions, probably adds more clarity than confusion. But I’d be happy to be proved wrong, and it probably depends a lot on the situation.

My semi-relevant blog post from a few years ago: Hierarchy of mechanisms for limiting copyright and copyright-like barriers to use of Public Sector Information, or More or Less Universal Government License(s).