本研究以管理當局及分析師年度最後一次預測值來探討管理當局及分析師盈餘預測品質之差異，以及盈餘預測之發佈是否成為經理人員操縱盈餘的誘因之一。故全文分為兩大研究主題：(1) 在台灣獨特的盈餘預測機制下，內外部盈餘預測資訊品質的差異 (2) 公司管理當局預估當期盈餘可能低於預測盈餘時，經理人員為避免股價下跌及遭不滿的投資人控訴，是否可能採用各種盈餘管理的方法向上操縱盈餘，以達到預測目標值。除此之外，我國上市電子公司研究發展支出比重較高，管理當局是否會利用研發支出來進行盈餘管理，亦為本研究探討重點之一。 本研究以民國88年五90年有發佈盈餘預測之上市電子公司為樣本，將樣本分為「對照組」與「操縱組」並使用迴歸模式、簡單平均模式及隨機漫步模式來探討操縱組之公司相對於對照組公司而言，在裁決性應計項目、處分資產損益、處分投資損益、營業外損益以及研發費用等各種可能的操縱工具上，是否有顯著的不同。 本研究實證結果顯示：(1) 外界分析師與管理當局盈餘預測資訊的資訊品質，並無顯著之差異。(2) 公司經理人員會利用裁決性應計項目、營業外損益、處分資產、處分投資及研發費用來操縱盈餘使盈餘增加，以達到預測值。

A Research on the Relationships between Earning Forecasting Precision and Earning Management by Inner Managers and Outer Analysts The focus of this paper is to compare the quality of earning forecasting between managers and analysts, and whether the earning forecasting announcement would be one of the motivations to manipulate earnings, by using the last forecasting value of electronic industry from 1999 to 2011. Two main subjects of this paper would be: First, the information quality variance between inner and outer earnings forecasting under the unique earnings forecasting system in Taiwan’s capital market. Second, would the management upwardly manipulates the earnings to avoid the stockholders’ complain when the management recognizes the possibility that the actual earnings would be lower than the prediction. Furthermore, we discuss whether the R&D expense would be the earning manipulation tool of electronic industry as it often forms a large potion of costs. We categorize the samples into experiment and control groups. We use regression model, average mean model and random walk model to compare the effects of the manipulation of accrual items between above two groups. The resu1ts of this research show that (1) there is no significant earning forecasting difference between inner management and outer analysts; (2) the management might upward manipulate discretional accrual accounts in order to accomplish their prior earnings forecasts.