台北市房價泡沫知多少？—房價vs.租金、房價vs.所得Is There a Housing Bubble in Taipei? Housing Price vs. Rent and Housing Price vs. Income

過往探討國內房市泡沫化的文獻，往往僅從租金收益的單一角度去衡量房價基值。但對於自有住宅比例較高的台灣而言，家戶所得不僅代表購屋者的負擔能力，更是構成房價基值的重要因素。有鑑於此，本研究分別從租金收益及家戶所得兩種不同的角度出發，分別建立房價基值模型以分析泡沫化現象，並使用可估計不可觀察變數的狀態空間模型來推估泡沫價格。實證分析台北市從1973至2008年間之房價，發現在1988~1990年房市泡沫化時期，所得與租金推估之泡沫規模均達到高峰，泡沫價格分別占市價約47%與54%的高比例。而在2008年房價持續上漲的情況下，兩者泡沫價格亦呈現相同上升之走勢，所得與租金所推估之泡沫價格約佔市價38%與27%，這顯示目前房市有泡沫化之跡象。不論從家戶所得或是租金收益兩者所推估之泡沫價格都有一致的表現，顯示本研究對泡沫價格的估計有相當的穩健性。
關鍵詞：房價、租金、所得、泡沫價格、狀態空間模型

This paper focuses on different fundamental models that derive the market fundamental housing price as a sum of the expected present value of rent or permanent housing income. By applying the State-Space Model and using the housing price in Taipei from 1973Q1 to 2008Q1, this paper tests whether there was a housing price bubble. The findings point out that the bubble existed in Taipei from 1988 to 1990, and the bubble accounted for 47% of the housing price from the housing income model (54% from the rent model). Moreover, Taipei’s housing prices rose consistently in 2008 and the bubble price estimated by the income model was close to 38% of the housing price (27% by the rent model). Accordingly, both the price-income ratios and price-rent ratios are useful indicators reflecting the rationality of the housing price.
Key words: housing price, rent, income, bubble price, state-space model