Review of Economic Studies · 2020 · J. Vernon Henderson、Tanner Regan、Anthony J. Venables
中文摘要
我们对城市的建设过程进行建模，估计模型参数，并计算改变土地用途时遇到的制度摩擦所造成的福利损失。我们区分正规建造技术与贫民窟建造技术；与贫民窟建筑不同，正规建筑可以建得很高、经久耐用，且建成后不可改造。随着城市发展，各区域最初以非正规方式开发，随后转为正规开发，之后进行周期性再开发。我们将贫民窟建模为一种技术选择；然而，土地市场中的制度摩擦可能阻碍其向正规用途转换，而这种转换需要有保障的产权。利用内罗毕2003年和2015年的独特数据，我们提出了一组支持模型假设的新事实，估计了模型的全部参数，并计算了用途转换摩擦造成的福利损失。我们追踪城市的动态演变，并将其与模型预测进行比较。在城市核心区的正规部门，约三分之一的建筑在12年间被拆除并由新建筑取代，新建筑的平均高度为原建筑的三倍。对于靠近市中心的较老区域中的贫民窟，即使在买断贫民窟房东的权益之后，克服制度摩擦仍将带来折合每个贫民窟家庭约18,000美元的收益，相当于贫民窟家庭通常每年支付租金的三十倍。
Abstract
Abstract We model the building of a city, estimate parameters of the model, and calculate welfare losses from institutional frictions encountered in changing land-use. We distinguish formal and slum construction technologies; in contrast to slums, formal structures can be built tall, are durable, and non-malleable. As the city grows areas are initially developed informally, then formally, and then redeveloped periodically. Slums are modelled as a technology choice; however, institutional frictions in land markets may hinder their conversion to formal usage that requires secure property rights. Using unique data on Nairobi for 2003 and 2015, we develop a novel set of facts that support assumptions of the model, estimate all parameters of the model, and calculate welfare losses of conversion frictions. We track the dynamic evolution of the city and compare it with model predictions. In the core city formal sector, about a third of buildings were torn down over 12 years and replaced by buildings on average three times higher. For slums in older areas near the centre, even after buying out slumlords, overcoming institutional frictions would yield gains amounting to about ${\$}$18,000 per slum household, thirty times typical annual slum rent payments.