The Open Definition (formerlyOpen Knowledge Definition)[1] is published by theOpen Knowledge Foundation (OKF) to defineopenness for any type ofdata,content, or otherknowledge. The definition's stated purpose is to "[make] precise the meaning of ‘open’ with respect to knowledge".[2] Although it draws philosophically from both theopen-source andfree software movements, the Open Definition prioritizes license compatibility overcopyleft principles requiring derivative works to be released under a free license. The Open Definition contains requirements for content licenses to be consideredopen licenses, and the OKF maintains a list of compatible licenses. The definition also requiresopen access,machine readability, and the use ofopen formats. The OKF's Open Software Service Definition is derived from the Open Definition.
TheOpen Knowledge Foundation (OKF) is a United-Kingdom-basedNGO[3] that began work on the definition in 2006.[4] According to the OKF, the Open Definition is "substantially derivative" ofBruce Perens'Open Source Definition and intends to continueRichard Stallman’s "ideals ofsoftware freedom".[2] The Open Source Definition, which is the most widely used criteria for determining if alicense is open source,[5] is itself is derived from the Debian Free Software Guidelines.[6] Although it is similar toDavid Wiley's defunctOpen Content License (which allows retaining, revising, remixing, reusing, and redistributingopen content works), the Open Definition is more specific.[2] It is concerned with freedom of access and reuse, rather thanopen governance.[6] The definition's stated purpose is to "[make] precise the meaning of ‘open’ with respect to knowledge".[2]
The definition (version 2.1) contains the following summary: "Knowledge is open if anyone is free to access, use, modify, and share it—subject, at most, to measures that preserve provenance and openness".[6][7] The previous version (1.0) stated that "A piece of content or data is open if anyone is free to use, reuse, and redistribute it — subject only, at most, to the requirement to attribute and/orshare-alike."[6] The new version makes it clear that usingdigital rights management (DRM) technology to reduce openness is not allowed.[6]
The definition contains detailed criteria for open knowledge.[2] In terms ofopen data, the definition covers the four main aspects:[8][9]
As such, the requirements of the Open Definition extend beyond open licensing by also requiring the elimination or reduction of technological barriers and pricing.[10][11]
The definition lists nine areas in which the license must be open and seven restrictions that may be placed on the content.[7] The OKF maintains lists of compatible and incompatible licenses that can be applied to knowledge.[2][7] As of 2017[update], it was recommending, in particular, six licenses.[7] It would be possible to draft a bespoke license that met the definition, but this practice would likely lead to compatibility issues in the event of reuse.[12] With the Open Definition,copyleft provisions—requiring reuse of content to be available under a free license—are allowed but not encouraged. The focus is more on license compatibility.[13] Licenses that are noncommercial-only (prohibiting use of content for financial gain) or do not allowderivative works do not meet the Open Definition.[13][1]
Most of the community involved inopen data supports the Open Definition over competing ones, such as that offered by the technology firmGartner—which only covers use and redistribution.[14] The value that the Open Definition provides as a standard is maintaining license compatibility and preventing the openness of data from being reduced by data sharing and reuse policies.[15]
In contrast to some other definitions of open knowledge, the Open Definition requires freedom of reuse as well as freedom of access.[16] Thus, manyopen access scientific publications do not meet the Open Definition.[17]
The OKF's Open Software Service Definition requires that thesoftware service's code befree and open-source software and any non-personal data be available under the Open Definition. Lawyer Andrew Katz criticizes this definition for not doing enough to guarantee transparency and preventvendor lock-in, which occurs when a company makes it deliberately difficult for users to switch to another service. He suggests that adding requirements for a fully documented and freely availableAPI and bulk data export could mitigate lock-in.[18]
