Non-audit services and audit quality --- the effect of Sarbanes-Oxley Act

There has been controversy over the restrictions that SOX imposes on non-audit services. Using accounting conservatism as a proxy for earnings quality of financial statements, the paper investigates whether the offerings of non-audit services by auditors impairs earnings quality. And then, to validate the effects of SOX, this paper also explores the association between non-audit services and accounting conservatism before and after SOX enacted. The empirical results show that non-audit services do impair earnings quality before SOX, but yields no conclusive results whether the provision of non-audit services affects earnings quality. This result supports the positive effects of the regulations of SOX in governing the independence of auditors.