School greenness and children's academic achievement and well-being: A population-wide study from Norway

Schools and their proximal surroundings are key environments for children's learning and development. While emerging evidence suggests that school surrounding greenness may support cognitive performance and well-being of students, the role of neighborhood characteristics in shaping these relations remains insufficiently understood. This study examined whether the greenness surrounding schools was associated with school-level academic achievement and well-being, and whether these associations vary according to neighborhood socioeconomic status (SES) and urbanicity. We linked nationwide administrative school-level data with geospatial measures of surrounding greenness for 2745 primary and lower secondary schools, representing more than 636,000 students. Outcome measures covered academic achievement and indicators of well-being, which were linked to NDVI values derived from 200-m buffers and school catchment areas, together with catchment-based socioeconomic status and population density. Associations were analyzed using linear mixed-effects models. Covariate selection was guided by a directed acyclic graph (DAG). Overall, surrounding greenness showed weak or no direct associations with academic achievement and well-being outcomes. However, SES and urbanicity moderated these school-level relationships. Greenness predicted higher mathematics achievement in low-SES but not in high-SES neighborhoods. Regarding well-being outcomes, surrounding greenness appeared protective in compact urban schools, where higher NDVI was linked to less bullying and greater thriving. These findings underscore that analyses of school greenness must account for neighborhood socioeconomic context and urbanicity, as these factors critically shape the direction and magnitude of associations at the school level.