Sometimes you need to compare reported data that has been reported against different standards or different versions of the same standard.

Sometimes you have existing data prepared against one standard and you need to produce a new report against a new standard. It would be helpful if as much data as possible could be reused from the old report.

Alternatively, one might have an existing report prepared against one standard and another report prepared against a different standard and to make the data comparable, we need to apply a mapping (from one standard to the other standard) to one of the data sets so we end up being able to compare the reports.

A document, a concordance, for capturing how to transform data reported against one standard to a different standard would enable the above use-cases.

A concordance defined by a regulator or other NGO and made available as a public good would avoid each preparer and consumer coming up with their own imperfect equivalent.


To compare reports prepared against standard A with reports prepared against standard B, one needs a concordance that says how to translate reports so that they are all against the same standard.

A concordance could be a list of assertions that simply map from taxonomy A
to taxonomy B:

A concordance could be more detailed so an assertion could show how to translate whole tables rather than just concepts:

  • From dimensional to non-dimensional
  • Items that do not map to target taxonomy
  • A sum of multiple source items


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XBRL International is a global not for profit operating in the public interest. Our purpose is to improve the accountability and transparency of business performance globally, by providing the open data exchange standard for business reporting.