开发时滞在房价上涨中的中介效应研究

因开发时滞已成为限制房屋供应效率的核心因素,受国内土地杠杆不断提升现象启发,我们试图验证两者的作用机制.我们首先利用实物期权模型,建立更贴近实际的二重随机微分方程,定量测算土地杠杆和开发时滞的非线性交互机制.局部均衡模型显示,在市场预期稳定的情况下,土地开发周期主要由土地杠杆(即土地价值与房屋价值的比例)决定.2002-2015年全国31个省域的面板数据回归结果显示,在有效控制人口密度等外部因素的影响后,平均来看,土地杠杆每提高100个百分点,当年开发时滞提高20个百分点.在经过时间趋势、外生事件冲击和地区位置等稳健性检验后,这一结论仍然成立.继而,建立三阶段中介效应模型,计算得到整体的中介效应为46%,但随着土地杠杆的提升,相较于时滞的间接途径,直接成本效应已成为影响房价的主要途径.而在此过程中,开发时滞对房价的影响始终是相对稳定且显著的.同时,土地杠杆存在类似的加速器效应,即随着从较低状态提高到较高状态,土地杠杆对房屋价格的正向溢出效应更强,作用力度提高约80%.上述研究证实,忽视土地杠杆过高对房地产市场的负面作用、单纯从需求端控制房价可能是不足的,凸显了从土地供给端进行结构性改革的重要性,需要将管理开发时滞纳入房地产调控整体政策框架中.

Research on the intermediary effect of development lag in the rise of house price

In view of development lag has become the core factor to limit the efficiency of housing supply. Inspired by the continuous upgrading of domestic land leverage, we try to verify the mechanism of land leverage and development lag. We first use real option model to establish a more practical double stochastic differential equation and partial equilibrium model shows that when the market expectation is stable, the land development cycle is mainly determined by the land lever (i.e. the ratio of land price to housing price). In the past 2002-2015 years, the panel data regression of 31 provinces in China showed that, after controlling the external factors such as population density effectively, on average, the land leverage increased by 100 percentage points, and the development lag increases 20 percentage points. This conclusion is still stable after the test of the time trend, the impact of exogenous events and the location of the region. Then, the three stage mediating effect is established, and the overall mediating effect is 46% with the promotion of land leverage, the direct cost effect has become the main way to influence housing price compared with the indirect way of development lag. At the same time, there is a similar accelerator effect in land leverage, that is, with the improvement from lower to higher level, the positive spillover effect of land leverage on housing prices is stronger, and the effect is increased by about 80%. The study highlights the importance of structural reforms from the land supply side which implies the importance of effective management of development lag as well as land leverage in the overall policy framework of real estate regulation.