The Quality and Usability of XBRL Filings in the US

In 2009, the US Securities and Exchange Commission (SEC) required all public companies and mutual funds to report their financial information to the SEC using a markup language called eXtensible Business Reporting Language (XBRL). The purpose of this requirement was to improve the accessibility to financial accounting data, increase the information flow between companies and investors, and make it easier and cheaper to collect and analyze data. Some controversy exists whether the benefits from using XBRL based data outweigh the costs associated with the creation of data and the use of the data. As part of that discussion, some claimed that the XBRL filings are of low quality and are difficult to use. The purpose of this paper is to examine the quality and usability of XBRL filings by examining different filing characteristics and mistakes over time. The focus of this paper is on the following characteristics: the use of extended tags, Document and Entity Information (DEI) errors, scale errors, and sign switches. Findings suggested that starting in 2012, there has been a steady improvement in the quality and usability of the XBRL filings in most aspects. Additionally, it seems that the lower quality and usability originates in data in the notes to the financial statements and in data filed by smaller companies. The results presented in the paper are consistent with the notion of companies moving along a learning curve and improving the quality and usability of the XBRL data as they gain more experience tagging. These improvements make it easier to use the XBRL filings and reap the benefits offered by this data. However, in spite of the efforts and improvements, it seems like more work is needed to continue improving the quality of the data