Housing prices tend to be higher in city centers than elsewhere. This phenomenon is known as the urban rent. The cause of this observed difference kindled a yet unsettled scientific dispute between two opposing models: Does urban rent stem from global economic speculation based on a location advantage, or is urban rent the result of an actors-driven valuation of central neighborhoods that leads to the augmentation of housing prices? This controversy is epitomized by the debate surrounding gentrification, i.e. the replacement of lower income inhabitants by higher income ones in poor neighborhoods. Two main models of gentrification have been proposed: the economic exogenous approach integrates gentrification in macro-scale speculation and the geographic micro-scale approach considers the neighborhood effect of high valued houses. These models describe how gentrification might happen, but fail to explain why neighborhoods suddenly become attractive although their locations do not changed. I propose to test the role of urbanity in the gentrification process so as to address this shortcoming. I am building an index of urbanity based on empirical observations (pre-existing density, social diversity and functional variety) and on residents’ aspirations for urbanity (evaluated according to their political choices and interviews). Moreover, I am building a statistical model to test the interaction between urbanity (both actual, measured urbanity and preferences for urbanity), macro-scale market dynamics and micro-scale local valuation. This model will test the following hypothesis : the level of urbanity changes the relative role of market dynamics and local valuation. I will present the first results of this research and the maps of my field study: San Francisco Bay Area.
