本研究主要探討台北信義捷運線開工後，且住宅位於捷運影響範圍之內（實驗組）與影響範圍之外（控制組），其住宅價格是否產生差異。使用差異中之差異法（difference-in-difference method）對住宅內部屬性，以及地理資訊系統（geographical information system, GIS）測量後之住宅外部屬性，進行實證模型的建立。採用吉家網2004至2006年度台灣不動產成交行情公報資料，包括中正區、大安區、信義區共三個行政區之住宅成交資料。實證結果顯示，捷運開工之後，將實驗組與控制組兩者之差距扣除其實驗組原本趨勢後，在800公尺範圍下，得到因捷運開工之真正影響為92.772萬。

This study investigated whether the housing prices for houses within the range of influence of the Taipei mass rapid transit (MRT) system (treatment group) and houses outside the range of influence (control group) differed after the new Xinyi MRT line began operation. The difference-in-difference method was used to measure internal housing characteristics and a geographical information system (GIS) was used to measure external housing characteristics; afterwards, an empirical model was created. The GigaHouse website was referenced to obtain public records on housing transactions in the Zhongzheng District, Da’an District, and Xinyi District between 2004 and 2006. The results indicated that, after correcting for the difference in housing prices between the two groups and the original pricing trend for houses in the treatment group, the opening of the new MRT line increased the cost of housing by NT$927,720 for houses within 800 meters of the MRT.