雖然企業同時會利用實質性活動與裁量性應計來進行盈餘管理，然而過去針對會 計師任期與盈餘管理的研究卻忽略了實質性活動的盈餘管理。本研究認為忽略這個因 素衍生三項重要的研究議題。首先，任何宣稱會計師任期可以抑制盈餘管理的論述可 能過度陳述。第二，如果實質性盈餘管理是應計類盈餘管理的替代性工具，那麼當企 業面臨一位具備較佳抑制應計類盈餘管理能力(如長任期或產業專家)的會計師時，在有 高度盈餘管理動機時，是否會更積極地從事實質性活動的盈餘管理。最後，如果任期 長短與盈餘品質的關係是一個內生性的關係(如會計師任期短的公司，他們會同步進行 實質性活動的盈餘管理以及應計類盈餘管理)，那麼過去關於長任期會計師可以抑制較 多盈餘管理的主張，可能就有所偏誤。因此，本研究擬將總盈餘管理區分為應計類盈 餘管理以及實質性盈餘管理，以瞭解任期與產業專家對於總盈餘管理的影響。 Most empirical research that examines the relation between auditor tenure and earnings management focuses on accrual-based earnings management (hereafter accruals management). Nevertheless, earnings management is not only through accrual-based manipulation but also through real activities. The overlook of earnings management through real activities (hereafter real earnings management) in past studies generates three important issues should be addressed. First, accruals management and real earnings management make up the total earnings management. Specifically, any studies based only on accruals management claims that long auditor tenure (as well as auditor expertise) can constraint earnings management of companies may be overstated, because total earnings management includes accruals and real approaches. Second, real earnings management is a substitute of accruals management. The concept is supported in Cohen, Dey and Lys(2008) by comparing accruals and real earnings management in the pre and post SOX environments. An interesting issue is whether firms who have high incentive to conduct earnings management but the firms whose auditors are with high expertise (e.g., long client tenure or industry expertise) will more aggressively conduct earning management through the real activities. Finally, I provide an approach to examine whether there is a potential endogenous problem between tenure and earning management. Suppose that the firms with short auditor tenure have worse earnings quality, because they conduct earnings management thorough accruals management and real earnings management concurrently. Therefore, prior conclusions support that long tenure can decrease the level of earnings managements can be improper. According to the explanations aforementioned, this study will divide total earnings management into accruals management and real earnings management in order to analyze the relation between auditor tenure (as well as auditor expertise) and total earnings management. In addition, I will systematically examine the relation between accruals management and real earnings management.