折舊係指資產價值隨時間經過而降低者；於不動產市場中普遍認知，因建築物發生實質毀損致使不動產價值呈現遞減趨勢。折舊之相關實證研究中，許多研究以屋齡及屋齡平方為自變數進行迴歸分析，兩者之係數往往達顯著性水準，顯示不動產價值在建築物耐用年數期間呈現價值先降後升的逆折舊現象，致使不動產價值遞減的折舊觀點受到質疑。本文以台北市房地產交易價格與租金資料進行複迴歸分析，於分別建立價格模型與租金模型後，自不動產交易價格中分離出使用價值與再開發價值，進行屋齡效果分析。研究發現不動產價值逆折舊現象，導因於不動產使用價值與土地再開發價值的交互作用，致呈現先降後升之現象。

Depreciation reflects the decline in an asset's value over time. The value of real estate will decrease gradually due to the building's physical deterioration. Most empirical studies thus adopt age and age-squared as proxies to measure depreciation, and the variables are often statistically significant. The empirical results suggest that there exists an upturn in the value of a property following a period of falling values over the property's economic life. Doubt is therefore cast on the conventional belief of a downward-only trend in property value. This article adopts multi-regression analysis to examine the pattern of use value and the redevelopment value of properties in Taipei City. The results show that the reversion of real property depreciation is due to the interaction of use value and redevelopment value. Therefore, a higher building age might yield a greater land redevelopment value.