Applying a license to your data permits you to set terms and conditions managing what others can do with your data, ensuring that Open Data can be (re)used optimally and can lead to innovative and valuable applications. If you don’t apply for one, all rights are omitted, meaning that nobody can use your data in any circumstances.
Different organizations provide free, easy-to-use licenses to make a simple and standardized way to give the public permission to share and use your work on conditions of your choice. For example, Creative Commons (CC), is a global not-for-profit organization that provides six main licenses to promote sharing and reuse. These are summed up below, and you can click on each license to see what its logo is.
- CC Attribution 4.0 International (CC BY 4.0): allows others to copy, distribute, display, perform and create derivate works, even for commercial purposes, but only when you are listed as a creator. This is the most open license and is recommended for the maximum distribution and use of licensed material.
- CC Attribution-ShareAlike 4.0 International (CC BY-SA 4.0): this license is the same as the former, but derivative works must be distributed under the same license as the original. Therefore, all new works based on your works have the same conditions, so all derived works may also be used e.g. for commercial purposes. Mind that it is difficult to combine separate SA sources.
- CC Attribution-NonCommercial 4.0 International (CC BY-NC 4.0): allows others to copy, distribute, display and perform the work, and to create derivate material based on your work as long as it has no commercial purposes and only if you are listed as the creator. CC Attribution-NonCommercial-ShareAlike 4.0 (CC BY-NC-SA 4.0): this license is the combination of the three licenses listed before. This means that others can do everything with your material, as long as you are listed as the creator of the work, the work is not used commercially and derivative works are distributed under identical conditions. CC Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0): lets others reuse the work for any purpose, including commercially, however, it cannot be shared with others in adapted form, and credit must be provided to you.
- CC Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND): This license is the most restrictive of these six licenses. This only allows others to download and share your works with others, as long as they leave the work intact and do not use it commercially.
In addition to this, the CC also provides the “no copyright reserved” option, called CC Zero (CC0). It effectively means relinquishing all copyright and similar rights that you hold in a work, and placing the work in the public domain to the extent legally possible, worldwide. CC Public Domain Mark allows anyone to mark a work that is already free of copyright restrictions around the world.
If you are depositing your data in a repository, you will probably be required to select a license for your data. Make sure that you familiarize yourself with the different types of licenses first, to choose the one that best meets your requirements. The CC has a simple tool to help you with determining the most appropriate one, and you also get some instructions on how you can implement the chosen license in your work.
However, some journals, repositories, etc. already have chosen and implemented one (or more) type(s) of a license, that applies to all published data. For example, all research articles accepted by scientific PLOS journals, are automatically published under a CC BY License.
Another organization named Open Data Commons also gives three types of conformant licenses, more particularly for databases. These are called PDDL, ODC-By, and ODC-ODbL, and are identical in content to the previous licenses CC0, CC BY and CC BY-SA, respectively. For licensing source code and software, there are also different types available and click here if you need to know one.
Data originated from the Flemish Government are frequently licensed under one (or more) of three model licenses determined by the government itself (web page in Dutch).
Again, a helpful guide for choosing a license (both for data and software) is found here.
In case of doubt about the usefulness of data for commercial purposes contact the Valorisation Office.