Why do people move: An area-based exploration of intra-urban migration in Sydney and its relationship with built environment factors

Intra-urban migration is closely linked to urban socio-spatial transformation, with built environments acting as potential “push” and “pull” factors. However, the role of built environments in driving aggregate-level intra-urban migration in Sydney, which is crucial for assessing urban planning effectiveness, remains insufficiently understood. This study examines Sydney's intra-urban migration patterns from 2006 to 2021 and applies the gravity model and Multiscale Geographically Weighted Regression (MGWR) model to identify built-environment-related push and pull factors while accounting for spatial variance. The findings reveal that: (1) Intra-urban migration intensified in Sydney, particularly in the west. (2) Sufficient housing, more detached dwellings, and less non-private housing in the destination incentivized population inflows, while these same attributes at the origin discouraged outflows. Spatial variations in migration drivers were observed: detached housing discouraged short-distance inflows but promoted long-distance inflows. West-to-east movers tended to relocate to areas with fewer detached homes but more owner-occupied housing, while westward movers displayed an opposite trend. The relationship between schools and relocation also exhibited east-west spatial variance, potentially linked to the lower quality of education in the west. The study suggests that the city government consider a differentiated spatial housing market to meet different needs and enhance efforts to improve the quality of urban infrastructure in the west to address spatial inequality. These findings contribute to a better understanding of built environment factors within the push-pull framework of intra-urban migration concerning spatial heterogeneity, providing valuable insights for optimizing urban infrastructure planning and population (re)distribution in rapidly transforming metropolitan areas.