The extension of income data at sub-national level is part of the OECD work on advancing the measurement agenda of wellbeing to regions and cities (see http://www.oecd.org/regional/how-is-life-in-your-region.htm). Income-based measures of poverty at regional level are a first step towards more encompassing metrics of deprivation that include non-monetary measures. High disparities between regions can undermine national economic grow'th, leading to inequality of opportunities and creating social tensions that in turn may sustain regional imbalances over time (OECD, 2011b).