A network analysis of income inequality

Though originally introduced to route mail more efficiently, postal codes are widely used for a number of mapping applications that aim to capture trends across broad geographical areas (e.g., for monitoring and planning purposes). Colombia implemented a national code system in 2009, adopting a total of 3677 codes (1,393 for cities and 2,284 for urban areas, each code associated with a longitude and latitude coordinate representing the centroid of the postal zone). The aim of this proposal is to enable a better understanding of the impact of geographic proximity on income inequality, using publicly available tax information at the postal code level. Our goal is twofold: (i) to evaluate whether there are structural patterns across so-called proximity networks, that is, models of relationships in which a node represents a postal code and a link represents the geodesic distance between them; and (ii) to compare the evolution of patterns of systemic inequality with countries with more developed economies, in particular, the United States. The activities of the seed money grant focus on advancing our ability to quantify income inequality in Colombia, laying the groundwork for the development of a larger project that will seek funding from international sources and promote the development of strategic mechanisms for cooperation (action plans) based on empirical comparative studies.