初探臺灣房價與所得空間排序之關係

Abstract

台灣高收入的個體主要集中於北部城市，這樣的區域收入不平等情形有不斷加劇的趨勢，2020年北部城市居民收入水平位於最高十分位距的比例比南部城市高出一點五倍。由於房價佔生活成本中很高的比重，因此房價是個體在選擇居住地時的重要因素，然而房價對於不同收入級距的影響程度有所不同。本研究以二階最小平方法來估計房價對於收入空間排序的影響，並使用一個類Bartik工具變數做為房價的工具變數。結果顯示，房價上漲導致一鄉鎮的較低收入群體的人口減少，對較高收入群體的人口影響較小。因此，隨著一鄉鎮的房價上升，其較低收入居民的比例下降，而較高收入居民的比例相應增加。此外，房價變動對於移入者的收入分佈影響較大，對於移出者的收入分佈影響較小。這表明個體的決策更受到他們移入鄉鎮的房價影響，而不太受到他們離開的鄉鎮房價影響。

Residential income segregation is a growing trend in Taiwan, with higher-income individuals predominantly concentrated in northern urban areas. By 2020, the proportion of top-income residents in northern cities is 1.5 times higher than in southern cities. House prices play a crucial role in residential choices as they can greatly impact living costs. However, the impact of house prices varies across income levels. This study uses a Weighted Two-stage Least Squares framework with a Bartik-like instrumental variable for house prices to identify the impact of house prices on income sorting. The results show that increasing house prices leads to a reduction in the population of lower-income groups, with minimal effects on higher-income groups. Consequently, as house prices rise in a township, there is a decrease in the proportion of lower-income residents and a corresponding increase in higher-income groups. Furthermore, the study reveals that changes in house prices have a more significant influence on the income distribution of in-migrants compared to out-migrants. This suggests that individuals' decisions are more influenced by the house prices of the destination they are moving into than the house prices of the origin they are moving out from.