The Components of Urban Growth in Developing Countries

Abstract

This report is concerned with the question of what share of urban population growth is due to natural increase and what share is due to rural to urban migration flows. This question is particularly salient in developing countries, where more of the world’s population growth is occurring and where urbanization trends are the fastest. This study revisits the issue of the driving mechanism for urban growth, aiming to assess the relative contribution of natural increase and rural to urban migration. This issue has been considered in two prior publications of the United Nations. The first provided both a broader discussion of urban and rural population growth more generally, as well as a presentation of the method for studying the components of urban growth using the Census Survival Ratio Method (United Nations 1980). The second report continued the analysis on the components to urban growth with the same basic methodology and using updated data from a larger number of countries (United Nations 2001). The current study greatly expands the empirical range by including data on 248 censuses from 76 countries. We focus attention on certain specific assumptions underlying the methodology. In particular, we examine the methodological limitations to help to understand the extent to which the overall assessment of the components of growth may (or may not) be affected by these assumptions. These additional analyses provide further insight into the sensitivity of estimates of the components of urban growth.

Urbanization Is No Longer Driven by Migration in Low‐ and Middle‐Income Countries (1985–2015)

“…We reiterate that, despite heterogeneity in urban definitions, natural growth is the main contributor to urbanization in contemporary transitions in low-and middle-income countries (Preston 1979;United Nations 2001;Stecklov 2008;Chen, Valente, and Zlotnik 1998;Jedwab, Christiaensen, and Gindelsky 2015;Farrell 2017). Our analysis has expanded on previous research, namely by Chen et al (1998), by covering all low-and middleincome countries (and not only those with censuses), and by extending to a more recent period.…”

“…Although, historically, internal migration contributed considerably to urbanization, in contemporary developing countries between the 1960s to 1990s, only around 40 percent of urban growth is attributable to migration (together with reclassification) across regions (Preston 1979; United Nations 2001; Stecklov 2008; Chen, Valente, and Zlotnik 1998; Jedwab, Christiaensen, and Gindelsky 2015; Farrell 2017). However, research also suggests considerable variation between regions in their urbanization process (United Nations 2018; Cohen 2004).…”

“…33See Stecklov (2008) for extensive explanation on the estimation of child migrants and the underlying fertility assumptions.…”

Urban Change in the United States, 1990–2010: A Spatial Assessment of Administrative Reclassification

“…This is often justified by considering reclassification a nuisance to the demographic processes contributing to urban growth. A frequently cited figure attributing roughly 60 percent of urban growth to natural increase and 40 percent to migration and reclassification combined [11] is based on a comparative study of fewer than 40 countries across three decades, undertaken more than 20 years ago based on decadal change estimates up to 1980 [3,12], and thus should be treated with caution. Even more importantly, none of the existing investigations have used spatial methods to explore these issues, despite the fact that spatial processes are a critical component of changes related to reclassification.…”

Using the T‐EFA method in a cellular automata‐based urban growth simulation's calibration step

“…In addition to population growth, rent-oriented land-use policies also cause the urban space to expand physically and are defined as urban growth.Urban growth is a complex socioeconomic process that transforms the built environment and rural areas into urban settlements with increasing population, while shifting the spatial distribution of the population from rural areas to urban areas (UN, 2019). Urban growth has three components: natural population growth, migration, and reclassification (Stecklov, 2018). In addition to these, urban growth depends on the demographic changes in a country (Dyson, 2011), the size of the settlement unit (Batty, 2008), spatial planning policies (Angel, Parent, Civco, & Blei, 2011), and physical and local conditions specific to the urban area.…”