A Comparison of Two Methods for Measuring Land Use in Public Health Research: Systematic Social Observation vs. GIS-Based Coded Aerial Photography

Public health researchers have identified numerous health implications associated with land use. However, it is unclear which of multiple methods of data collection most accurately capture land use, and “gold standard” methods vary by discipline. In this paper, five desirable features of ecological data sources are presented and discussed (cost, coverage, availability, construct validity, and accuracy). Potential accuracy issues are discussed by using Kappa statistics to evaluate the level of agreement between datasets collected by two methods (systematic social observation (SSO) by trained raters and publically available data from aerial photography coded using administrative records) from the same blocks in Chicago. Findings show that significant kappa statistics range from .19 to .60, indicating varying levels of inter-source agreement. Most land uses are more likely to be reported by researcher-designed direct observation than in the publicly available data derived from aerial photography. However, when cost, coverage, and availability outweigh a marginal improvement in accuracy and flexibility in land use categorization, coded aerial photography data may be a useful data source for health researchers. Greater interdisciplinary and inter-organization collaboration in the production of ecological data is recommended to improve cost, coverage, availability, and accuracy, with implications for construct validity. Abbreviations CMAP Chicago Metropolitan Authority for Planning CCAHS Chicago Community Adult Health Study SSO Systematic social observation GIS Geographic information systems Two Methods for Measuring Land Use in Public Health Research 3