Links between reports
Links can be made between reports to reference related information.
Sustainability disclosures frequently refer to data published in other documents, for example, financial reports. A report can include a footnote stating where a given fact originated and providing a link to view the original report. This method may cause the referred data to be difficult to find and verify. The most precise way to refer to data from other documents is to link directly to that data. In digital reporting, links should be easy to follow by interested parties such as auditors, regulators, and consumers.
Sustainability reports typically link to:
- Other sustainability reports
- Financial reports
- Certification documents
XBRL standard and linking between reports
In the XBRL standard, it is possible to refer to data published in another report in multiple ways:
- The recommended method is linking directly to a fact in another report.
Data preparers can link precisely to another structured digital document by creating a targeted link that uses an inline viewer. By using a link to an inline viewer it is possible to link directly to a fact. In the viewer, the Fact Properties pane is displayed allowing the data to be examined. A simple HTML link between one inline XBRL and another inline XBRL document does not display the Fact Properties pane. - Data preparers can also use common HTML hyperlinks to link to a non-structured digital document, for example, a PDF file.
In this method, it is important to provide as many details about the linked data as possible. Data consumers should be able to easily find and consume that linked data. Standard setters should define what kind of additional description should be added to the links when data preparers use this method. - Other methods of linking, for example referring to paper documents, are difficult for both humans and machines to consume.
Example
A data preparer is reporting sustainability data and needs to add a general link to the company’s financial report so that the report can also be examined by the data consumers.
The data preparer adds a link that uses a viewer so that the financial report is useful to the data consumer:
https://www.xbrl.org/financialstatements/2020/xii-financial-statements-2020-viewer.signed.html
Further into the report, the data preparer needs to link directly to a fact within the financial report. The data preparer, again using a viewer, adds the following link:
More detail
Precise linking
When data preparers link to a structured digital document, XBRL allows them to link not only to the report itself but precisely to specific information within that report. For example, a link that points to another XBRL report can link directly to a report fact when the link uses an inline viewer.
Links that point to non-structured digital documents can only point to the documents, and not to particular data within those documents. The links must have an additional description to explain where exactly data consumers can find the referred information within the documents.
Standards defining links
Standard setters need to make sure that when data preparers add links to their reports, those links are precise, well-explained and trustworthy. Standard setters, in their taxonomies, can define requirements that data preparers must meet when adding links to their reports.
Standard setters can create a structure within their taxonomies to collect information about the links. For example, the taxonomy may need to specify:
- Location of the document
- Type of the document
For example, an XBRL document. - Location of the data within the document
For example, when linking to a PDF document, data preparers will have to specify the page number with the relevant data.
Validating links
When a report is validated, links in that report go through that validation process as well.
- If a link points to a non-structured digital document, the validation process checks if the link was captured according to the XBRL taxonomy requirements.
For example, the validation process checks if the data preparer specified the page where the linked data can be found in the linked document. - If a link points to a structured digital document, the validation process compares the linked data with the data that is presented in the report.