本研究旨在探討國內會計師任期與會計保守程度之關聯性，並評估國內審計準則公報46號之規定會計師每七年輪調政策之良窳，另外，也延伸探討事務所任期、事務所規模對會計保守性之影響。本研究以1996年至2002年上市公司共計1673個觀察值為樣本，並採用Basu (1997) 的盈餘報酬迴歸模型來衡量會計保守性與時效性。依循2009年法規之規定，將會計師任期區分為未超過七年與七年以上，結果顯示，會計師任期與會計保守性有非線性關係，會計師任期越長，是可使盈餘報導更加保守，但超過七年，反而會使盈餘報導變得不保守。在不連續事務所任期樣本中，長任期相對於短及中任期，盈餘報導會較保守，亦指事務所任期於長任期下，盈餘報導會較保守。再者，本研究也發現由四大事務所查核的公司，其盈餘報導之保守性會顯著優於非四大事務所查核的公司，顯示由四大事務所查核，盈餘報導會較保守性。從會計保守性觀點，本研究實證結果支持審計公報48號規定會計師每7 年應進行所內會計師輪調之規範，另外，也發現事務所於長任期及由四大事務所查核是可讓盈餘報導更加保守。 This study investigates the relations between auditor tenure and the level of accounting conservatism, and evaluate whether seven-year audit partner rotation requirement specified in the Auditing Standard Bulletin No. 46 is needed. In addition, we also extent to investigating the effect of audit-firm tenure and audit-firm size on the level of accounting conservatism. Our samples include 1673 observations of TSE (Taiwan Stock Exchange) firms from 1996 to 2002, and we measure of conservatism and timely based on Basu (1997) asymmetric timelines of earnings model. From the view point of 2009 regulation, we next partition the sample into less 7 years and excess 7 years based on the length of auditor tenure. our empirical evidence reveals that nonlinearity in the relation between conservatism and auditor tenure. The longer the auditor tenure, the better report of conservative earning, but excess 7 years results in lower report of conservative earning. In nonlinearity audit-firm tenure, the results indicate that report of conservatism earning is higher for longer tenure and relatively lower short tenure and medium tenure, suggest the report earnings conservatism when audit-firm tenure is longer,. Secondly, we find that reporting of conservative earnings of Big four clients is significantly higher than for non-Big four clients, suggest reporting of conservative earnings for Big four clients is conservatism. From accounting conservatism view, our empirical evidence support to Mandatory CPA Rotation’ rule in Taiwan since 2009, in addition, finding that reporting of conservative earnings for audit-firm tenure in longer and Big four clients is conservatism.
