Many believe that financial data, available via public filings (with the S.E.C.), is clear and objective, that for every item, there is one correct number, and that the relative quality of databases depends on the accuracy of transcription. The good news is that transcription is easier than ever thanks to the SEC’s having pushed companies to use the automated XBRL protocol. The bad news is that most of what we use in our models does not consist of directly-recorded numbers.
Instead, we typically work with “standardized” databases that involve a lot less science and a lot more art than many realize. Accordingly there’s considerable room for differences in numbers many might assume ought to be the same across all database vendors.
Portfolio123 uses Compustat as its data vendor, considered to be the highest (institutional) quality historical fundamental data.