When encountering a data set online, in the absence of an explicit license, it is prudent to treat the data as copyrighted material and to contact the copyright holder(s) to secure permissions for use. The assignment of licenses to data sets adds clarity around permissions for use/re-use and eliminates the need to contact the copyright holder unless one wishes to secure rights above and beyond those granted by the license.
Below is a list of licenses commonly used in data repositories.
CC0 (Creative Commons Zero)
Using CC0, you can waive all copyrights and related or neighbouring rights that you may have in all jurisdictions worldwide, such as your moral rights (to the extent waivable), your publicity or privacy rights, rights you have protecting against unfair competition, and database rights and rights protecting the extraction, dissemination and reuse of data. Because copyright laws differ around the world, you may use this tool even though you may not have copyright in your jurisdiction, but want to be sure to eliminate any copyrights you may have in other jurisdictions.
CC-BY (Creative Commons Attribution)
Materials licensed with a CC-BY licensed must be given appropriate attribution including a link to the licenses. Users of the material must indicate if changes were made. No additional restrictions apply, and as such, the license permits others to copy and redistribute the material in any medium or format and to adapt (remix, transform, build upon the material) for any purpose, even commercially.
CC-BY-SA (Creative Commons Attribution Share Alike)
Materials licensed with a CC-BY-SA licensed must be given appropriate attribution including a link to the licenses. CC-BY-SA permits others to copy and redistribute the material in any medium or format and to adapt (remix, transform, build upon the material) for any purpose, even commercially. If you do adapt the material, you must distribute your contributions under the same license as the original, namely CC-BY-SA.
Creative Commons offers other licensing options that are less popular for data sets but still widely used for other applications. Note that the Creative Commons Public Domain Mark (“no known copyright”) is not recommended for use with data.
Open Source Licenses
These licenses are intended to be used for code.
- BSD (Open Source Initiative 3-Clause BSD License)
- Apache License 2.0 (Apache Software Foundation 2.0 License)
Other licensing options
Licenses can have federal jurisdiction or be specific to a repository. Some examples include: