Area-based deprivation indices (ABDIs) have become a common tool with which to investigate the patterns and magnitude of socioeconomic inequalities in health. ABDIs are also used as a proxy for individual socioeconomic status. Despite their widespread use, comparably less attention has been focused on their geographic variability and practical concerns surrounding the Modifiable Area Unit Problem (MAUP) than on the individual attributes that make up the indices. Although scale is increasingly recognized as an important factor in interpreting mapped results among population health researchers, less attention has been paid specifically to ABDI and scale. In this paper, we highlight the effect of scale on indices by mapping ABDIs at multiple census scales in an urban area. In addition, we compare self-rated health data from the Canadian Community Health Survey with ABDIs at two census scales. The results of our analysis confirm the influence of spatial extent and scale on mapping population health-with potential implications for health policy implementation and resource distribution.KEYWORDS Deprivation indices, MAUP, Population health, Scale.
A BRIEF BIOGRAPHY OF POPULATION HEALTH INDICES COMMONLY USED IN CANADAThe use of census data to quantify socioeconomic deprivation is a generally wellaccepted method of identifying populations with poorer health outcomes.1-5 The history of census-based area deprivation indices dates back to at least until 1971, when the Department of the Environment (DOE) in the United Kingdom used data taken from the census to identify localities where a high proportion of households were exposed to adverse social and economic conditions. 6 The indices were developed to more effectively identify areas in need of resources to improve quality of life. Publications stemming from The Black Report, 7 the Whitehall, 8 and Acheson studies 9 launched additional public scrutiny of the relationship between socioeconomic gradients and health status. These studies have spurred a relatively new yet increasingly popular framework that uses socioeconomic data taken from the census to quantify deprivation and demonstrate its relationship with population health. 2,[10][11][12][13][14] Schuurman, Bell, and Oliver are with the