Is it Possible to Avoid a Lemon? Reflections on Choosing a Poverty Mapping Method

Poverty and food security in most countries are highly heterogeneous phenomena, making it common to find wide spatial variability. Both types and depth of poverty, measured in a variety of ways, vary between and within countries, regions or other geographic and administrative units. Spatial heterogeneity can develop for a variety of reasons, including differences in geography, history, ethnicity, and access to markets and public services, infrastructure, and other facets of public policy (see, for example, Bloom and Sachs, 1998, Jalan and Ravallion, 2000, or de Janvry and Sadoulet, 1997). Heterogeneity in poverty and food security is often hard to measure correctly, however, with conventional analytical tools. The key problem is obtaining data which permits the measurement of poverty and food security at a level of disaggregation sufficient to capture the heterogeneity brought on by spatial variability. The concept of mapping involves measuring the incidence of poverty and food security by some predetermined area. While the term “poverty” mapping has become ubiquitous in research and policy circles, an almost unlimited variety of poverty and food security indicators can be mapped with the methods described in this paper. Although poverty and food security are not necessarily the same concept, the terms are used interchangeably in this paper since here the focus is on methods, not specific indicators.