Defining Socially-Based Spatial Boundaries in the Region of Peel, Ontario, Canada

Census Tract data for Peel were derived from the 2006 Canadian Census Master file.Following correlation analysis to reduce the data set, Principal Component Analysis was applied to the data set to reduce the complexity and derive an index. The Getis-Ord Gi*statistic was then applied to look for statistically significant clusters of like Census Tracts. A detailed decision tree for the amalgamation of remaining zones and ground-truthing with Peel staff verified the resulting zones.A total of 15 Data Zones that are similar with respect to socioeconomic and sociodemographic attributes and that met criteria defined by Peel were derived for the region.The approach used in this analysis, which was bolstered by a series of checks and balances throughout the process, gives statistical validity to the defined zones and resulted in a robust series of Data Zones for use by Peel Public Health. We conclude by offering insight into alternative uses of the methodology, and limitations.Independent of individual characteristics, it is recognized that an individual's immediate environment possesses both material and social characteristics that are linked to health status as well as health-seeking behaviours [1-3]. That is, health reflects both individual characteristics, as well as the characteristics of the neighbourhood which constrains and enables individual health. For example, neighbourhoods may provide important information and support with regard to health practices and behaviours, but may also be associated with poor health in cases where crime is higher or the physical environment is poorer [4]. Concurrently, there is a common need for health status and related data to be represented at the 'neighbourhood' scale, whether it is for the provision of social welfare programs, planning, or health care delivery.Geographers have long been concerned with defining neighbourhoods and places, and examples of techniques to define neighbourhoods abound in the academic literature [see, for