The purpose of this paper is to analyze the PCAOB's inspection reports of large, annually inspected accounting firms. The inspection reports identify audit deficiencies that have implications for audit quality. By examining the inspection reports in detail, we can identify the nature and severity of audit deficiencies; we can track the total number of deficiencies over time; and we can pinpoint common, recurring audit deficiencies. We focus on large accounting firms because they play a dominant role in the marketplace (i.e., they audit public companies that comprise approximately 99 percent of U.S.-based issuer market capitalization). We document a significant, downward linear trend in the number of deficiencies from 2004 to 2009. We also identify common, recurring audit deficiencies, determine the financial statement accounts most often impacted by audit deficiencies, and isolate the primary emphasis of the financial statement impacted. Our findings generally are consistent comparing Big 4 and second-tier accounting firms, though a few differences emerge. In addition, we make comparisons with findings that have been documented for small, triennially inspected firms.
Data Availability: The data are available from public sources.