公部門不動產估價成效評估──公平性之觀點

Evaluating the Performance of Property Assessment in the Public Sector-An Equity Perspective

公部門對於不動產所為之大量估價，常常作為財政收入以及土地政策的價格基礎，其重要性不言可喻。但是受限於時間、人力與經費，估價的偏誤在所難免。臺灣採用區段地價制度，多年來遭致不少批評，但是大多缺乏具體的證據。本文認為大量估價首重估價的公平性，回顧相關文獻研究後，有系統地分析台北市內湖區與南港區之估價與市場資料。實證結果顯示區段地價制度成效頗佳，然而未來應特別著重在各地價區段間，以及新舊發展區間估價比值的一致性。此外，屋齡、建物面積和土地面積與不動產價格間的非線性關係，可能是造成估價偏誤的主要原因。

Property assessment undertaken by the public sector is essential to taxation and land policies. Thus, a reliable assessment system is required. However, assessment errors are inevitable due to constraints of time, manpower and budgets. The valuation zone system employed in Taiwan has often attracted criticism but such criticism generally lacks convincing evidence. This study first reviews the methods for evaluating the performance of property assessment. The suitability of such methods is first considered and the methods are then applied to systematically examine property assessment in the Nei-hu and Nan-gang districts of Taipei city. The current valuation zone system is found to have performed satisfactorily in that only very minor vertical inequity is detected. However, the empirical evidence also suggests that more attention should be paid to the inconsistency of assessment ratios among valuation zones, and between areas at different phases of development. In addition, the nonlinear relationship between a structure's age, floor area and land size and its property value is likely to be responsible for the assessment errors detected.