SAR-Gi: Taking a spatial approach to understand food deserts and food swamps

Most existing food deserts/swamps studies adopted non-spatial approaches,overlooking the role of spatial dependence in the associations between food access and socioeconomic status. This study aims to fill the gap by examining this relationship with a spatial perspective. Using Austin, Tx as a case study, we adopted a multi-mode Huff-based 2SFCA method to measure the spatial access to food stores. Eight socioeconomic variables were represented by two indices per factor analysis:Economic Deprivation Index (EDI) and Sociocultural Deprivation Index (SDI). We proposed a SAR-Gi* model to characterize food deserts/swamps in Austin. Our analyses reveal that EDI is a significant predictor for access to healthy food (β = -0.054, p = 0.037), and SDI is significantly associated with access to unhealthy food (β= 0.160, p = 0.000). We also found that food deserts and swamps in Austin are concentrated in the east and northeast of Austin, respectively. The noticeable difference between the spatial patterns of food deserts and food swamps as identified by our study and those based on the USDA definition or other traditional methods speaks to the great potential of the SAR-Gi* model in reflecting geographical patterns and relations embedded in food access and socioeconomic status of neighborhoods. •SAR-Gi* is developed to help identify food deserts and food swamps.•Economic/Sociocultural Deprivation Indices (EDI/SDI) measure socioeconomic status.•Access to healthy/unhealthy food is significantly related to EDI/SDI respectively.•Food deserts and food swamps are in the East and Northeast Austin.•Different intervention strategies are recommended in food deserts and food swamps.