The socioeconomic status of urban neighbourhoods can change over time due to multiple processes. Some of these processes operate at the urban level, which cause neighbourhoods to change relative to one another within the urban area. The movement of neighbourhoods up and down the urban socioeconomic hierarchy is often related to their life cycle and stage of development; many neighbourhoods decline as they age, and at some point might be subject to renewal processes which lead to an upward trajectory. Beyond the urban level, neighbourhood socioeconomic conditions are also affected by structural processes that involve regional, national and global levels. These processes can generate changes in the distribution of socioeconomic characteristics of the population in an urban area, which can translate into neighbourhood change. Two different ‘structural’ effects change the distribution of neighbourhood average incomes in the urban area: The ‘growth/decline’ effect which increases or decreases incomes among all neighbourhoods in the urban area, and the ‘inequality’ effect which increases the disparities among them.
The way neighbourhood change has been measured in most research on neighbourhood socioeconomic change does not enable to distinguish between these different components of change. The commonly used measures of change, which rely on the relative positions of neighbourhoods within the cit-context, exclude the effect of overall growth or decline and confound the effects of urban positional exchanges with the effect of increase in inequality. By using the standard practices it is impossible to estimate the effects of structural processes on neighbourhoods. It is also impossible to systematically compare processes of neighbourhood change across cities, while accounting for the absolute conditions in neighbourhoods.
This research project introduces an application of a method to decompose total neighbourhood socioeconomic change measured in absolute terms into its contributing components. The method was originally developed for understanding income mobility of individuals. The approach enables to take account of all distributional processes that generate neighbourhood socioeconomic change, while distinguishing between them. The method promotes systematic analysis and is used to substantiate the role of inequalities in urban socio-spatial change. The project also aims at applying the method to various case studies in order to provide empirical evidence on underlying processes of neighbourhood change and their effect on urban socio-spatial structures.
The applications of the proposed method demonstrates the need to move beyond relative measures of neighbourhood change due to its overcoming of two main problems of contemporary research. First, it highlights the importance of measuring change in absolute terms, which gives a more complete picture on socio-spatial dynamics. Secondly, it demonstrates how the effect of inequality can be distinguished, and how the separation of this effect is critical to drawing valid conclusions about neighbourhood change processes.
