Tim Berners-Lee has suggested a 5-star scheme for grading the quality of open data on the web, for which the highest ranking is Linked Open Data:’

  • 1 star: data is openly available in any format.
  • 2 stars: data is available in a structured format, such as Microsoft Excel file format (.xls).
  • 3 stars: data is available in a non-proprietary structured format, such as Comma-separated values (.csv).
  • 4 stars: data follows W3C standards, like using RDF and employing URIs.
  • 5 stars: all of the other, plus links to other Linked Open Data sources.

See Linked Data terminology and technologies, Interoperability should be a goal in itself