License - How to use and share the data

Data with a license clearly establishes rules on how everyone can modify, use, and share data. Without a license, these rules are unclear, and can lead to problems with attribution and citation. Two licenses that are well suited for data sharing are:

  1. Creative Commons Attribution 4.0 International Public License (CC BY), and
  2. Creative Commons CC0 1.0 Universal (CC0)

Other licenses or notices to be aware of are copyrighted data, and data embargoes. If you are working with data already copyrighted, (for example under CC BY or CC0), you must follow appropriate guidelines for giving credit. Data may also be under embargo. This means data cannot be shared more widely until a specific release time. If sharing data under an embargo, include detailed information on the embargo requirements in: the README, and in separate correspondence with those who receive the data. Databases may also be licensed with the Open Data Commons Open Database License:, which provides provisions for sharing, creating, and adapting, provided that work is attributed, shared, and kept open.

Once you decide on a license, you should provide a LICENSE file that contains the entire license in the top level of the directory.


The CC BY enforces attribution and due credit by default, but gives a lot of freedom for its use. Data can be shared and adapted, even for commercial use, with the following conditions:

  • You must provide appropriate credit to the source. This means listing the names of the creators.
  • Link back to the CC BY license, and
  • Clearly show if changes were made.
  • Data cannot be sub-licensed, that is - a change to the existing license
  • There is also no warranty, so the person or people who obtained the data cannot be held liable.

For a brief overview of the CC BY, suitable to include in a README, see ccby-short. For the full license, see ccby-long.


The CC0 is a “public domain” license. Data with a CC0 license means the data owners waive all their rights to the work, and it now “owned” by the public. The data can be freely shared, copied, modified, and distributed, even for commercial purposes without asking permission. When using data with CC0, it is good practice to cite the original paper, but it is not required. For a brief overview of the CC0, see cc0-short, and for the full license, see cc0-long.