本研究以消費者剩餘與住宅需求滿足家戶數來評價住宅自有率高低的意涵,從個體家戶租擁選擇效用極大化的角度出發,建立一個「住宅自有率個體基礎模型」,經由理論模型推導與Cobb-Douglas效用函數設定,除提供利率對於住宅自有率的影響不甚明顯(Painter and Redfearn, 2002)、恆常所得增加會使家戶偏向擁屋(Steven, 1979;Goodman, 1988)、預期未來房價上漲會使家戶偏向擁屋(Goodman, 1988;Dusansky and Koc, 2007)等過去文獻的理論基礎外,更發現恆常所得增加使家戶偏向擁屋,需家戶早已偏好擁屋下才會成立;預期房價上漲使家戶偏向擁屋,其實是一種尚未完全前瞻性思考的預期現象。住宅自有率是否愈高愈好,需看何種因素(變數)造成與原先住宅自有率的水準才能定論;在一個國家(或地區)的家戶具有兩階段式消費行為且偏好擁屋、市場房貸利率高於一般利率、原先的住宅自有率水準較高但不至於高到租屋率為零等前提下,若住宅自有率的攀升是由於擁屋成本減少或所得增加所致,此時住宅自有率愈高愈好;反之,若住宅自有率的攀升是由於租屋成本增加或預期未來房價折現值增加所致,此時住宅自有率愈高愈不好。
This research uses consumer surplus and housing quantity demand to evaluate homeownership rates, builds a microfundation model of homeownership rates by households’ maximum utility behaviors, and utilizes comparative analysis and simulation to confirm interest rate and homeownership rates are unconnected (Painter and Redfearn, 2002), permanent income increasing make households prefer to own a house (Steven, 1979;Goodman, 1988), expected future housing price rising make households prefer to own a house (Goodman, 1988;Dusansky and Koc, 2007). This research finds that permanent income increasing make households prefer to own a house is under the condition that households have already preferred to own a house, and expected future housing price rising make households prefer to own a house is under the condition that households might not have forward-looking expectation. This research also finds that whether homeownership rates are higher are better or not, it’s depended on what factors (variables) and initial homeownership rates are. If households have two-stage consumption behavior, housing mortgage interest rate is higher than interest rate, the initial homeownership rates are higher but not to make tenant rates zero, homeownership rates grew by purchasing cost decreasing or income increasing are better; by rental cost increasing or expected future housing price rising are worse.