Specifically, Big 4 auditors represent high audit quality, while non-Big 4 firms represent low audit quality. This is based on the assumption that the Big 4 always provide superior audits that communicate the reliability of unobservable financial reports. Of course, this is not to suggest that non-Big 4 companies intentionally deviate from U.S. GAAP or other relevant reporting standards. However, Teoh and Wong (1993) find that the amounts of deviation of reported numbers from actual economic levels are higher for non-Big 4 auditors. DeAngelo (1981) identifies Big 4 firms as an adequate proxy for high audit quality as the brand name and size assume greater reliability due to technical expertise. According to Sori et al (2006), Big 4 employees are more qualified and have access to better financial resources, research facilities and technology. This gives them a competitive advantage to conduct broad or specialized audits and a greater ability to discover errors or inaccuracies. This argument is supported by the low levels of accounting restatements issued compared to those of non-Big 4 auditors (Eshleman and Guo 2014) and their extensive specialized training programs (Khurana and Raman