How We License Data

Choosing a License

Users have three options for choosing a license:

Open Database Commons Public Domain and Dedication License (PDDL)

PDDL is similar to the well-known CC-0 license (, in that users licensing their data under PDDL put the data out freely without any restrictions whatsoever. This allows creative uses of data that the original author may not have envisioned.

Open Database Commons Attribution License (ODC-BY)

ODC-BY allows anyone to freely use uploaded data, with the only restriction being that data have to be cited when used. Users who choose this license can specify exactly how they want to be cited. This is useful for cases when uploaded data are related to a published study and it is desirable that anyone who uses the data cites the study.

Custom License

For special cases where PDDL or ODC-BY will not work, users can write their own license and apply it to their data.