School greenness and student-level academic performance in Santiago, Chile

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BACKGROUND AND AIM: Previous research suggests greenness exposure might foster children’s learning and improve academic performance. However, evidence on the association between school greenness and academic outcomes is mixed, with most studies looking at school-level associations in developed countries of the northern hemisphere. We present preliminary results from an observational study evaluating the association between school greenness and student-level academic performance in Chile METHODS: Satellite-derived school greenness estimates were linked to administrative data on academic outcomes and contextual student and school information. We included all 4th grade students (n=246,774) enrolled in 1,398 public, charter, and private schools within the Greater Santiago Area (GSA) between 2014 and 2018. Academic performance was measured as individual-level scores in mathematics and reading standardized tests. Greenness in a 100m buffer around schools for each year was estimated using Normalized Difference Vegetation Index (NDVI) derived from Landsat 8 reflectance data. We fit linear multilevel mixed effects models to evaluate associations between school greenness and mathematics and reading scores, adjusting for students’ sex, age, maternal education, paternal education, household income, and attendance, and for schools’ SES, size, student-to-teacher ratio, and school type. RESULTS:We found that a 0.1 increase in school NDVI was associated with a 3.1 point increase (95%CI: 1.8-4.4) in mathematics scores, equivalent to an increase of 1.2% (95%CI: 0.4%-1.7%) in mean mathematics scores for the study population. For reading, a 0.1 increase in school NDVI was associated with a 0.8 point increase (95%CI: -0.4-2.0) in test scores, equivalent to an increase of 0.3% (95%CI: -0.1%-0.7%) in mean reading scores for the study population. Stratified analyses by school type showed that the impact of NDVI was more significant in public versus private and charter schools. CONCLUSIONS:Increased greenness was linked to improved standardized mathematics scores among elementary-aged students in a capital city in South America, with higher impact in public schools. KEYWORDS: Greenspace, Academic Performance, School Environment, Normalized Difference Vegetation Index (NDVI)