Uneven progress toward SDG 11.1 in Africa: a hierarchical clustering analysis of slum prevalence trajectories

Introduction Slum and informal-settlement prevalence varies widely across Africa, yet less is known about how countries have followed different paths over time. This study examines long-term patterns across African countries from 2000 to 2022. Methods The study used UN-Habitat data on the share of the urban population living in slums or informal settlements across 54 African countries. Countries were grouped according to similarities in their 23-year trajectories. Several checks were used to assess the reliability of the groups and examine whether the findings changed when different aspects of change were considered. Results Two broad groups were identified. The first included 34 countries with generally higher relative prevalence throughout the period, while the second included 20 countries with generally lower relative prevalence. However, countries within each group showed important differences in how their situations changed over time. Alternative analyses also produced some different groupings. Discussion The findings show that Africa does not have one common pattern of slum and informal-settlement prevalence. Countries differ not only in their relative levels but also in how these levels change over time. This suggests that progress towards SDG 11.1.1 requires policies that recognise country-specific trajectories rather than treating the problem as a uniform continental challenge.