Remix and compatibility

The ability to remix, adapt or re-purpose education material is a significant advantage of OER when compared to closed learning materials. Remix refers to the ability to combine different resources together to create new derivative works. Creators of Open Educational Resources (“OER”) often combine learning materials from a variety of sources together, or add their own creativity to existing works to create a new educational resource that they in turn re-license openly. However, the legal terms of one license may not be compatible with the legal terms of another license.

We need to consider the compatibility of different licenses when remixing materials, that is creating a derivative work. Note that license compatibility applies when creating derivative works. Reusing materials without adaptation is easy with Creative Commons as long as you comply with the original license conditions.

Defining detivative works

As license compatibility relates to derivative works or adaptations, we must first explain what Creative Commons means by a derivative work.

A derivative work is a work that is based on another work but is not an exact, verbatim copy. What this means exactly and comprehensively is the subject of many law journal articles and much debate and pontification. In general, a translation from one language to another or a film version of a book are examples of derivative works. Combining a number of Creative Commons licensed learning materials with your own original creations is also a derivative work.  Under Creative Commons’ core licenses, synching music in timed-relation with a moving image is considered to be a derivative work.

Under general copyright law, format shifting from one medium to another is considered a copy and therefore a derivative work. It's important to note, however, that the Creative Commons licenses allow the user to exercise the rights permitted under the license in any format or media, even in the No-Derivatives licenses. This means that, under the Creative Commons Attribution Non-Commercial No-Derivatives license, for example, you can copy the work from a digital file to a print file consistent with the terms of that license.

The compatibility challenge

It seems only natural to assume that an OER with a Creative Commons license could be mixed with another OER using a Creative Commons license or alternative open content license like the GNU Free Documentation License (GFDL). However, this is not the case. For example:

• A Creative Commons license with a No-Derivatives restriction means that it cannot be remixed with other Creative Commons licensed content because of the no-derivatives requirement;
• Different open content licenses may restrict remixing with other license types because of the specific licensing requirements for derivative works. For example, the GNU Free Documentation License requires that derivative works are released under the precisely the same license, meaning the GNU Free Documentation License. Therefore it is not legally permissible to mix GNUFDL content and release the derivative work under a CC-BY-SA license, even though these licenses are similar in terms of the intent of the licenses.

However, it is possible to release original works under a dual license, that is both Creative Commons and GFDL (Note original works are not derivative works, but dual licensing could facilitate greater flexibility for downstream remixing). It would also be possible to release a collection under their respective licenses, where the sub-sections can be clearly identified as discrete parts. In other words, parts of the material could be licensed with Creative Commons and part GFDL, provided that the original terms of the respective licenses are adhered to.

For the purposes of this tutorial, we will restrict our discussion of license compatibility among Creative Commons licenses and not address the complexities of compatibility among different licenses. If in doubt, when mixing content from licenses other than Creative Commons, get legal advice or contact the copyright holder for release of the work under a corresponding Creative Commons license.

Compatibility among different Creative Commons licenses

Nurturing the growth of the commons through derivative works.

Generally speaking, the more open the Creative Commons license of the source materials used for derivative works, the more options there are available for the licensing of derivative works. It is legally possible to add more restrictions than the original license in some cases, for example, releasing a derivative work under all rights reserved which incorporates source materials licensed under a Creative Commons Attribution license. However, as educators we should do our best to respect the original intent of the creator for releasing their works freely. In education, doing the right thing (sharing knowledge freely) is more important than doing things right (legal options for adding restrictions).

When remixing materials, educators should note that Creative Commons licenses that contain the Share-Alike license element (ie. Attribution Share-Alike, Attribution Non-Commercial-Share-Alike) require that derivative works (ie. the result of two combined works) must be licensed under the same license elements. So, you cannot, for example, combine an Attribution Share-Alike license with an Attribution Non-Commercial Share-Alike. However, it is for example, possible to incorporate Creative Commons Attribution materials with Attribution Share-Alike resources if the resultant work is released under the Attribution Share-Alike license. If you are combining a work licensed under a Share-Alike license condition, you need to make sure that you are happy and able to license the resulting work under the same license conditions as the original work.

At first, license compatibility appears confusing and complex, however the compatibility chart below will assist. When reading the chart, start with the license of the original work on the left. The green boxes indicate license compatibility. That is, you may use the license indicated in the top row for your derivative work or adaptation. The blank rows for the BY-NC-ND and BY-ND licenses indicate that derivative works or adaptations are not permitted by the license of the original work, therefore you are never allowed to re-license them.

Compatibility chart		License terms that can be used for a derivative work or adaptation
		BY	BY-NC	BY-NC-ND	BY-NC-SA	BY-ND	BY-SA	PD
Status of the original work	PD
	BY
	BY-NC
	BY-NC-ND
	BY-NC-SA
	BY-ND
	BY-SA

The above Compatibility Chart shows that resources under a CC BY license can be combined with resources licensed under any other CC license, and may be re-licensed under any other CC license. CC BY is the license most compatible with other CC licenses, and as a result, we recommend CC BY for use in OER. Unfortunately, you cannot apply a CC BY license to your OER if you have used or remixed materials available under our more restrictive licenses. Below we explain which licenses you may use, depending on the license terms of the underlying resources:

• Resources licensed under CC BY-NC can only be remixed, adapted, and re-licensed into resources containing an NC (Non-Commercial) term, which includes CC BY-NC, CC BY-NC-SA, and CC BY-NC-ND.
• Resources licensed under CC BY-SA and CC BY-NC-SA can only be incorporated into derivative works which are re-licensed under the same license (e.g. * BY-SA with BY-SA, and BY-NC-SA with BY-NC-SA) due to their SA (Share Alike) term. (However, it is for example, possible to incorporate CC BY with CC BY-SA resources if the resultant work is released under the CC BY-SA license).
• Resources licensed under CC BY-ND and CC BY-NC-ND cannot be incorporated into a derivative work, and therefore they may not be re-licensed, due to the ND (No Derivatives) term in the license.

Key points

Note that while derivative works can be released under different licenses, the Creative Commons license is irrevocable. This means that the original source materials used to create a derivative work will always be available under its original Creative Commons license. This is an important feature of Creative Commons licenses which protect the intentions of the original copyright holder and mitigates against exploitation of OER learning materials.

Test your license remix knowledge

OER remix game

In this short exercise you will consider a number of remix scenarios to explore license compatibility. The dealer will deal four cards, each representing an open educational resource (OER) you would like to aggregate for a derivative work. Each card has at its centre an icon representing its media type. The four media types are Text, Image, Audio, and Movie. Each card shows the license mark of the original resource. These could be Public Domain, CC-BY, CC-BY-SA, CC BY-NC-SA, and GNU FDL. Your intention is to include supporting text and guidelines for learners with each resource. In addition, you plan to author a preface for the compilation, thus the resultant work will constitute a derivative work. You will be able to choose an appropriate license for the derivative work in each example. The release of your own copyright must be compatible with the licensing requirements of the OERs used (For the purposes of this exercise you are not required to make value judgements about the license choice). You can progress to the next hand dealt by clicking on the green "next" arrow at the bottom of each page, or use the links below: Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 This activity is a remix inspired by the online version of David Wiley's OER remix game.

Feel free to try more examples by visiting the online version of the OER remix game (Note that this will require flash to play the game).

Summary

As you become more familiar with the licensing terms of the different Creative Commons licenses and start remixing educational materials license compatibility will become second nature. Remember these guidelines:

• Creative works dedicated to the public domain can be remixed with all the Creative Commons license types. (Remember that the Public Domain is not a license.)
• Generally speaking, you cannot re-license derivative works under more open licenses without prior consent from the copyright holder.
• The Creative Commons Attribution license can be re-licensed using any of the six license types
• You can never remix source materials containing a No-Derivatives restriction (however, format shifts are permissible)
• If you include any source materials using the Share-Alike provision, the derivative work must be released under the identical license. (You can include CC-BY materials in a CC-BY-SA or CC-BY-NC-SA licensed derivative work.)

Acknowledgements

Some content on this page was sourced from:

• License compatibility in the OER Handbook
• Creative Commons FAQs