According to the Open Knowledge Foundation, open data can be defined as data that anyone can "freely download, reuse and redistribute, subject only, at most, to the requirement of attribution and equal sharing". Its reuse by society, businesses, entrepreneurs and the public sector can generate economic, social and governmental benefits.
Today, more and more public administrations are opening up their data for reuse. To ensure that open data is reusable, a number of basic principles need to be met, which were agreed at a meeting of the Open Government Working Group in 2007:
- Complete: all data should be available, as long as it is not subject to privacy or security restrictions.
- Primary: data should be available from primary sources, without having been modified or processed in any way and at the most detailed level of granularity possible.
- Timely: data should be available as soon as possible to retain its value and be kept up to date in the same way.
- Accessible: data should be available without discrimination so that anyone can use, modify and share it for any purpose.
- Machine processable: the available data should be structured in such a way that it can be processed in an automated way.
- Non-discriminatory: data should be available to anyone without the need for any kind of registration.
- Non-proprietary: data should be available in a format that is not for the exclusive use of any entity to avoid restrictions on use.
- License free: public data shall not be subject to copyrights, licenses or patents.