Digital Reporting, Taxonomy, and Data Formats
Domain 7 tests structured reporting: how sustainability and financial data become machine-readable, what a taxonomy contains, and where tagging errors originate. Items typically ask you to distinguish formats, identify the correct tagging approach, or diagnose a consistency failure.
Core concepts
XBRL is the XML-based business reporting language. Inline XBRL embeds tags within the HTML report so the human-readable and machine-readable versions are the same document. A taxonomy is the dictionary of elements, with labels, references, calculation relationships and dimensional structure. Key taxonomies include the IFRS Accounting Taxonomy, the IFRS Sustainability Disclosure Taxonomy, and the ESRS digital taxonomy used within the European Single Electronic Format.
Tagging practice
Use a standard element wherever one exists; create an extension only when nothing fits, and anchor the extension to a standard element. Get the mechanics right: sign, scale and decimals, units, period type (instant for a balance-type fact, duration for a flow such as annual emissions), and dimensions such as segment or country. Every tagged fact must match the printed figure and the narrative.
Assurance and consumption
Regulators and investors increasingly consume filings as data, so tagging errors are disclosure errors. Consistency checks, calculation linkbase validation and version control of the taxonomy release are part of the control environment, not an IT afterthought.
Worked example
Tagging gross Scope 1 emissions of 118,000 tonnes of CO2 equivalent: select the gross Scope 1 element, unit tonnes of CO2 equivalent, decimals set to reflect rounding (minus three for thousands), period as a duration covering the reporting year, and no dimensions unless a breakdown is presented. Reasoning: using a reduction element, a negative sign, or an instant period would each produce a fact that a screening tool reads incorrectly even though the printed table looks right.
Traps that cost marks
- Using a superseded taxonomy version or a deprecated element.
- Excessive or unanchored extension elements.
- Mismatch between the tagged value and the printed figure.
- Confusing block tagging of a whole note with detail tagging of individual facts.
- Ignoring sign conventions and instant versus duration distinctions.