This latest episode of THE XBRL FILES looks at arcs. Arcs are the connective tissue of XBRL. They describe the relationship between XBRL objects and give reported facts their meaning. The four arc types are: 1) presentation arcs for statement formatting, 2) label arcs for naming elements, 3) definition arcs for defining dimensional elements and 4) calculation arcs for describing the arithmetic relationship between elements. Calculation arcs make XBRL data self-validating both within and between statements. They are essential in fully standardizing XBRL data by providing context for mapping extended and foreign concepts.
When companies fail to report all relevant calculation arcs, it's a problem. In this example, Generex Biotechnology Corp, using Novaworks Software, failed to report over half of the required arcs on it's income statement in its most recent 10K. XBRLogic's automated standardization failed as a result.
This is troubling on several levels. First, why didn't the company catch this error? It's ultimately responsible for a complete and accurate filing. Second, why did the Novaworks software allow the company to create an incomplete filing? Are its validation routines sufficient? If so, are they too easily overridden? And third, why doesn't the SEC enforce its rules and reject incomplete filings?
Unfortunately, errors like this are not uncommon. There are plenty of examples among all filer categories and all software vendors. Here's Schneider National's most recent 10-Q, using Workiva software:
