物價是目前最受關注的議題,本文以美國1979-2006年的18個主要大城市為研究對象,觀察各城市物價指數是否有收斂的情形。過去在討論區域經濟成長收斂的議題時,以新古典成長理論的收斂模型進行研究,因此將此應用於美國各城市物價之收斂分析中。 在採用區域資料時,由於可能存在空間相關性造成模型的誤差項有異質性的問題。因此在採取以市級為區域單位的美國物價收斂分析。以空間相關分析來檢定美國各城市物價指數是否具有空間相依的情形,在檢定中發現美國各城市物價指數具有正向空間相關,因此為了解決因空間異質性對模型的估計有偏誤的情形,因此輔以空間模型來進行估計。依資料的型態我們採用Panel data分析,因各城市有不同的區域特徵,所以固定效果加入空間落遲模型及空間誤差模型進行研究。 在我們的研究發現,在加入影響城市通貨膨脹的控制變數下美國各城市物價指數有條件收斂的情形。在控制變數方面,空間落遲係數及空間誤差係數具有正向空間關係,顯示各城市通貨膨脹因要素移動、技術擴散及知識外溢而有空間外溢效果。此外,在研究發現美國物價發展有一結構性改變,在實證分析發現美國物價指數在1995年以後收斂速度有變緩慢的情形。
Price is currently the subject of greatest concern, this paper we use 18 major cities in the United States, 1979-2006 to investigate, whether Price Index in U.S cities have a conditional convergence. In the past to discuss regional economic growth convergence issues, use convergence model of neo-classical growth theory to investigate, so this applied to the U.S. cities of price convergence analysis. When use regional data, regression may have a spatial correlation to cause heterogeneity of error term. Therefore, in order to take the city for the regional units of the U.S. price convergence analysis. Spatial correlation analysis of U.S. cities to test whether the Price Index has spatial dependence, the test found Price Index in the United States cities has a positive spatial correlation, in order to solve the heterogeneity of the regression cause an estimated bias, therefore we use spatial econometrics to estimate. According to the type of information we use Panel data analysis, because the cities have different characteristics of the region, to use the fixed effect in spatial lag and spatial error model. In our study found Price Index in U.S. cities have conditional convergence when we control regional characteristic variables. In the control variables, spatial lag and spatial error coefficient have a positive relationship between cities inflation because mobile of factor, technology diffusion and knowledge spillovers have a spatial spillover effects. In addition, the study found that Price Level in United States has a structural change, the empirical analysis found price index in the United States has convergence of the slow rate after 1994.