Introduction: In Australia, health and economic outcomes of urban developments have not been formally quantified. We address this using a method that could be applied to planned urban developments.

Methods: Health and economic outcomes were compared between three urban developments in Melbourne, Australia by combining a model estimating the probability of transport walking with a proportional multi-state multi-cohort life table model. Urban developments included a greenfield development, infill development, and a composite of highly walkable areas in Melbourne. Built environment features for each development and data on 16,890 adults from the Victorian Integrated Survey of Transport and Activity were used to simulate transport walking probabilities, which were then used in the proportional multi-state multi-cohort life table model to quantify health and economic outcomes between pairs of urban developments.

Results: If an adult population living in a greenfield development was instead exposed to an infill development then health benefits of 30 health-adjusted life years (HALYs), economic benefits of A$3 million and healthcare costs savings of A$0.1 million could be accrued. The benefits would be approximately 40% greater if they were exposed to highly walkable urban development. 36 HALYs gained, A$4 million of economic benefits, and A$0.3 health care costs savings were predicted if infill development residents were instead exposed to a highly walkable urban development.

Conclusions: Quantifying health and economic outcomes for different urban developments provides important information of the unassessed consequences of city design. This research demonstrates that more walkable neighbourhoods could significantly contribute to population health and the economy.