Wineman Ayala, Alia Didier Yélognissè, Anderson C Leigh
Daniel J. Evans School of Public Policy and Governance, University of Washington, Parrington Hall, 4100 15th Ave NE, Seattle, WA, 98195, USA.
J Rural Stud. 2020 Oct;79:254-268. doi: 10.1016/j.jrurstud.2020.08.014.
Designing effective policies for economic development often entails categorizing populations by their rural or urban status. Yet there exists no universal definition of what constitutes an "urban" area, and countries alternately apply criteria related to settlement size, population density, or economic advancement. In this study, we explore the implications of applying different urban definitions, focusing on Tanzania for illustrative purposes. Toward this end, we refer to nationally representative household survey data from Tanzania, collected in 2008 and 2014, and categorize households as urban or rural using seven distinct definitions. These are based on official administrative categorizations, population densities, daytime and nighttime satellite imagery, local economic characteristics, and subjective assessments of Google Earth images. These definitions are then applied in some common analyses of demographic and economic change. We find that these urban definitions produce different levels of urbanization. Thus, Tanzania's urban population share based on administrative designations was 28% in 2014, though this varies from 12% to 39% with alternative urban definitions. Some indicators of economic development, such as the level of rural poverty or the rate of rural electrification, also shift markedly when measured with different urban definitions. The periodic (official) recategorization of places as rural or urban, as occurs with the decennial census, results in a slower rate of rural poverty decline than would be measured with time-constant boundaries delimiting rural Tanzania. Because the outcomes of analysis are sensitive to the urban definitions used, policy makers should give attention to the definitions that underpin any statistics used in their decision making.
制定有效的经济发展政策通常需要根据农村或城市状况对人口进行分类。然而,对于什么构成“城市”地区并没有统一的定义,各国交替采用与定居点规模、人口密度或经济发展相关的标准。在本研究中,我们以坦桑尼亚为例,探讨采用不同城市定义的影响。为此,我们参考了2008年和2014年收集的坦桑尼亚具有全国代表性的家庭调查数据,并使用七种不同的定义将家庭分类为城市或农村。这些定义基于官方行政分类、人口密度、白天和夜间卫星图像、当地经济特征以及对谷歌地球图像的主观评估。然后将这些定义应用于一些常见的人口和经济变化分析中。我们发现这些城市定义产生了不同程度的城市化水平。因此,根据行政划分,坦桑尼亚2014年的城市人口比例为28%,但采用其他城市定义时,这一比例在12%至39%之间变化。一些经济发展指标,如农村贫困水平或农村电气化率,在使用不同城市定义进行衡量时也会有显著变化。像十年一次的人口普查那样,定期(官方)将地区重新划分为农村或城市,会导致农村贫困下降速度比用界定坦桑尼亚农村的固定时间边界来衡量时更慢。由于分析结果对所使用的城市定义敏感,政策制定者应关注其决策中所使用的任何统计数据背后的定义。