Mapping Transnational Gentrification in the Porto Metropolitan Area (Portugal): Development and Validation of a Multidimensional Index

Transnational gentrification, driven by tourism, lifestyle international migration and global real estate investment, is increasingly transforming Southern European cities. However, robust methods to quantify this phenomenon remain scarce, particularly at the metropolitan scale. We developed and validated a multidimensional transnational gentrification index for the Porto Metropolitan Area. Harmonised census block group data from the 2011 and 2021 Portuguese Censuses were combined with tourism-related indicators. Principal Component Analysis was used to construct the index from demographic, socioeconomic and housing variables capturing baseline and temporal changes. Construct validity was assessed against the European Deprivation Index, Property Tax Value and residents’ perceptions of neighbourhood change. Spatial clustering was examined using Global Moran’s I and Local Indicators of Spatial Association. The selected principal component comprised 16 variables reflecting increases in tertiary education, white-collar employment, foreign residents from high-income countries, short-term rentals and high housing rents, alongside decreases in older and unemployed residents. The index was positively associated with neighbourhood deprivation, increases in property tax value and tourism, population substitution and rising housing costs. Spatial analyses revealed clustering centred on Porto’s historic core and neighbouring municipalities. The index provides a valid, reproducible and potentially transferable measure of transnational gentrification and a tool for monitoring neighbourhood change and future research on the social, environmental and health impacts of gentrification.