Government data shall be considered open if it is made public in a way that complies with the principles below:

1. Complete

All public data is made available. Public data is data that is not subject to valid privacy, security or privilege limitations.

2. Primary

Data is as collected at the source, with the highest possible level of granularity, not in aggregate or modified forms.

3. Timely

Data is made available as quickly as necessary to preserve the value of the data.

4. Accessible

Data is available to the widest range of users for the widest range of purposes.

5. Machine processable

Data is reasonably structured to allow automated processing.

6. Non-discriminatory

Data is available to anyone, with no requirement of registration.

7. Non-proprietary

Data is available in a format over which no entity has exclusive control.

8. License-free

Data is not subject to any copyright, patent, trademark or trade secret regulation. Reasonable privacy, security and privilege restrictions may be allowed.

Compliance must be reviewable.

via 8 Principles of Open Government Data.