XBRL: How do you merge rows from different filings?

Question

We use a XBRL processor to ingest filings from SEC. Often times, a company declares a metric in different filings with different concepts - with or without exactly matching values - but to be regarded as the same financial metric. Essentially when you want to create a stitched view of all the filings, these numbers should appear on the same row. I'd provide an example to make it clear:

ASGN's 2020 10-K filing uses us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments to report EBT.

ASGN's 2021 10-K filing uses us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest to report EBT.

If you notice, even the figures for 2020 and 2019 do not match between the two filings. My question is - how do you reconcile these cases in code - to create a stitched/continuous view? Is this a solved problem or is it more of a process where you need to make manual interventions? Are there libraries that help with this? Is there mapping information available with the SEC that can be used - even when the data do not agree? Would be great if anyone can help with this. Thanks.

Answer 1

From personal experience I can give you a list of considerations when it comes to non-program-development people who work in the financial sector and submit standardized information:

1. the level of respect they have for the "you have to do things this way" paradigm is effectively 0.

2. expectance that filings aren't filled out properly/correctly should be at 100%.

3. Even though sec filings are meant to consolidate data in a standardized, meaningful, and readily available transparent facet, the financial sector is plagued with ambiguity and interoperable terms which may differ from corporate entity to corporate entity.

... or in short ... in their point of view "ILFCOBITEINI and ILFCOBITMIAILFEMI look pretty similar, so they pretty much mean the same thing."

As far as I know, there is no support on behalf of sec or other federation entities which is in charge of controlling sec filing accuracy since the idea is " you file it wrong... you pay a fine " .... meaning that due to interoperability of forms that "wrong" level is pretty ambiguous.

As such, the problem is that you must account for unexpected pseudo-fails when it comes to filings, meaning that you should probably write some code which does structural-to-content identity matches across different entries.

I'd advise using a reasoning logic subsystem (that you'll have to write) instead of a simple switch-case statement operating on a "if-this-exists-else" basis. ... and always consider that the level of incompetence in the financial sector is disgustingly high.