Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, 60208, USA.
Potsdam Institute for Climate Impact Research - PIK, Member of Leibniz Association, P.O. Box 601203, 14412, Potsdam, Germany.
Sci Rep. 2021 Nov 25;11(1):22918. doi: 10.1038/s41598-021-02327-7.
Urban scaling theory explains the increasing returns to scale of urban wealth indicators by the per capita increase of human interactions within cities. This explanation implicitly assumes urban areas as isolated entities and ignores their interactions. Here we investigate the effects of commuting networks on the gross domestic product (GDP) of urban areas in the US and Brazil. We describe the urban GDP as the output of a production process where population, incoming commuters, and interactions between these quantities are the input variables. This approach significantly refines the description of urban GDP and shows that incoming commuters contribute to wealth creation in urban areas. Our research indicates that changes in urban GDP related to proportionate changes in population and incoming commuters depend on the initial values of these quantities, such that increasing returns to scale are only possible when the product between population and incoming commuters exceeds a well-defined threshold.
城市规模理论通过城市内部人均人际互动的增加来解释城市财富指标的规模报酬递增。这种解释隐含地将城市区域视为孤立的实体，忽略了它们之间的相互作用。在这里，我们研究了通勤网络对美国和巴西城市地区国内生产总值（GDP）的影响。我们将城市 GDP 描述为一个生产过程的产出，其中人口、流入的通勤者以及这些数量之间的相互作用是输入变量。这种方法显著改进了城市 GDP 的描述，并表明流入的通勤者有助于城市地区的财富创造。我们的研究表明，与人口和流入的通勤者成比例的变化相关的城市 GDP 的变化取决于这些数量的初始值，使得只有当人口和流入的通勤者的乘积超过一个明确定义的阈值时，规模报酬递增才是可能的。
