Table 1.

Definitions of “urban” and “rural”.

		Definition/construction	Strengths	Limitations
1.	Administrative definition	The official designation in each country	Can be contextually specific (for example, accounting for high population densities in areas that are considered to be rural in nature)	Official definitions vary across countries (limiting the potential for cross-country comparisons) and sometimes are not clearly defined. Official categorizations may be influenced by political or other considerations.
2.	Population density	A household is categorized as urban if the local population density is at least 500 persons/km2 (from WorldPop).	Analysts can set their own threshold; can be consistent across countries	As a single indicator, this does not capture multidimensional understandings of “urban” spaces. Census data may be outdated.
3.	Impervious surface	A household is categorized as urban if the share of impervious surface cover is at least 2% (from the GMIS data set of Landsat).	Analysts can set their own threshold; can be consistent across countries	Small towns in low-income countries may have an urban character without the presence of impervious surfaces. This data set is available for only one year (2010).
4.	Night light intensity	A household is categorized as urban if the intensity of night light is at least 8 on a scale of 0–63 (from the NOAA DMSP-OLS Nighttime Lights Time Series data set).	Analysts can set their own threshold; can be consistent across countries	Small towns in low-income countries may have an urban character even without the energy infrastructure to support night lights. As of the time of writing, the data are not available in a readily useable format beyond 2013.
5	Africapolis	The designation of urban areas is provided by Africapolis, which bases its determination on the settlement population size (≥10,000) and the distance between buildings (within 200 m).	A consistent definition is applied in all countries, using information from censuses and satellite imagery. The outline of urban areas is made available in an easy-to-use format.	The rules used to identify urban spaces cannot be adjusted by the analyst. This data set is available for one year (2015).
6.	Local nonfarm economy	A household is categorized as urban if the average share of nonfarm income (excluding crop, livestock, or agricultural wage income) among the nearest 7 neighbors is at least 66%.	Explicitly measures the economic shift away from agriculture that commonly underpins the definition of “urban” spaces.	Requires detailed information on income-generating activities typically collected in resource-intensive (and infrequent) household surveys.
7.	Subjective assessment	A household is categorized as urban based on subjective assessment of Google Earth images. This labor-intensive categorization was applied only to the 2014 survey wave.	Can be contextually specific and multidimensional.	This method is labor-intensive and, by definition, subjective. Research assistants found it difficult to estimate with confidence the presence of amenities in the aerial view of communities.