Harmonizing Urban and Rural Definitions for Better International Comparisons

The Degree of Urbanisation manual, developed by six international organizations, standardizes the classification of cities, towns, and rural areas using a population grid for global comparability. This methodology enhances SDG monitoring, policymaking, and urban planning by providing a unified, cost-effective, and data-driven framework.

In an effort to standardize the classification of urban and rural areas worldwide, six international organizations—the European Commission, the Food and Agriculture Organization (FAO), the United Nations Human Settlements Programme (UN-Habitat), the International Labour Organization (ILO), the Organisation for Economic Co-operation and Development (OECD), and The World Bank have collaborated to produce a comprehensive methodological manual. This initiative, endorsed by the UN Statistical Commission in 2020, aims to address long-standing inconsistencies in how countries define cities, towns, and rural areas. The manual, titled Applying the Degree of Urbanisation, introduces a globally harmonized classification system designed to improve international statistical comparability, enable better policy planning, and facilitate the tracking of progress on the Sustainable Development Goals (SDGs).

The Degree of Urbanisation: A New Standard

The crux of the new classification is the Degree of Urbanisation, a system that divides all areas into three primary categories: cities (high-density clusters), towns and semi-dense areas (moderate-density clusters), and rural areas (low-density clusters). Unlike traditional methods that rely on national administrative boundaries, which can vary significantly from one country to another, this system employs a population grid approach to define urban and rural spaces. This ensures a more consistent and objective measurement of settlement patterns, reducing the biases caused by diverse administrative boundaries and providing a clearer picture of population distribution.

Historically, the definition of urban and rural areas has varied widely across countries. Some nations classify an area as urban based solely on population size, while others incorporate additional factors like economic activity, infrastructure availability, or legal status. These discrepancies make international comparisons difficult, particularly when assessing socio-economic indicators. The manual addresses this issue by establishing universal thresholds based on population size and density. For instance, urban centres are defined as contiguous grid cells with a population density of at least 1,500 people per square kilometer and a minimum total population of 50,000 inhabitants. Similarly, towns and semi-dense areas must have a density of at least 300 inhabitants per square kilometer and a total population of at least 5,000. Areas that do not meet these criteria are classified as rural.

Harnessing Geospatial Technology for Accuracy

A key advantage of the methodology is its reliance on geospatial technologies and census data to construct population grids. Countries with advanced statistical systems can generate these grids using geo-coded censuses or population registers, while nations with less detailed data can rely on satellite imagery, remote sensing, and mobile phone data to estimate population distribution. The manual acknowledges that some countries may face challenges in implementing this approach due to data limitations but encourages the use of alternative sources such as the Global Human Settlement Layer (GHSL) and WorldPop datasets, which provide globally available population estimates at high resolution.

Beyond defining cities, towns, and rural areas, the manual introduces an additional classification known as Functional Urban Areas (FUAs), which aims to capture the broader economic footprint of cities by incorporating surrounding commuting zones. A functional urban area consists of a core city plus its surrounding areas where at least 15 percent of the working population commutes to the city for employment. This approach recognizes that urban life extends beyond the administrative boundaries of a city and that policies related to transportation, housing, and infrastructure must consider the entire metropolitan region rather than just the urban core. By identifying functional urban areas, policymakers can better understand urban-rural linkages and develop strategies that address regional disparities more effectively.

Improving SDG Monitoring and Policy Implementation

One of the major benefits of this standardized classification is its application to monitoring the SDGs, particularly those focused on urbanization, infrastructure, and sustainability. Many SDG indicators require disaggregated data for urban and rural areas, yet inconsistent definitions have made cross-country comparisons difficult. By implementing the Degree of Urbanisation, governments and international organizations will have a common framework to assess progress on key issues such as access to clean water, electricity, education, and healthcare. This, in turn, enables better targeting of resources and interventions to areas in need.

The manual is not intended to replace national definitions of urban and rural areas but rather to complement them by providing a secondary classification that ensures international comparability. Countries can continue to use their own definitions for domestic policymaking while applying the Degree of Urbanisation for global reporting and analysis. This dual approach acknowledges the need for both national flexibility and global consistency, allowing for a more nuanced understanding of urban and rural dynamics.

A Cost-Effective and Scalable Solution

The methodology also emphasizes cost-effectiveness, as it can be applied to existing data sources without requiring extensive new surveys or data collection efforts. Many countries already have the necessary data in their censuses, registers, or satellite imagery. By leveraging these existing resources, the Degree of Urbanisation can be implemented with minimal additional financial burden while significantly enhancing the quality and comparability of urban and rural statistics.

As urbanization continues to reshape economies and societies worldwide, a common approach to measuring and understanding these changes is essential. The Degree of Urbanisation methodology represents a major step forward in providing a unified, transparent, and scientifically grounded framework for classifying cities, towns, and rural areas. With its adoption, policymakers will be better equipped to analyze trends, allocate resources effectively, and implement policies that promote sustainable development. By ensuring that data on urbanization is both accurate and comparable across nations, this initiative will play a crucial role in shaping global urban policies in the years to come.