"A piece of data or content is open if anyone is free to use, reuse, and redistribute it — subject only, at most, to the requirement to attribute and/or share-alike." - Open Knowledge Foundation Network(1)
What are we talking about when we mention open data? In public life, open data appears in a variety of ways and it is, therefore, appropriate to distinguish between the various categories of openness. The authors of the brochure 'How open is it'(2) have done this for open access to scientific publications. A similar way can be used to distinguish between the various categories of openness for research data. How open is the data really? What am I allowed to do, and what can I do with it?
Simply making data available – providing access – is often not enough to be allowed to reuse data. The data has to be available in a format and under a license that allows reuse. If, in addition, the data is also available in a linked data format, this results in new possibilities for use. Linked data have a certain structure(3) allowing for technical interoperability of datasets. This way data from a variety of sources can be easily linked.
The image map below is a representation of the various stages of openness of research data (mouse over the images for the text). An increasing degree of openness makes it easier to gain new knowledge from existing knowledge.