Diversity index as a metric for SDG 2.4: an analysis of municipalities in the state of São Paulo, Brazil

Purpose This paper addresses the lack of a standardized metric for analyzing SDG 2, Target 2.4, focusing on agriculture and food security. It examines the diversity of agricultural production in São Paulo’s municipalities to identify trends in specialization or diversification. Design/methodology/approach The study applies the Adjusted Simpson’s Diversity Index (SDI') and Exploratory Spatial Data Analysis (ESDA) in a time series from 1999 to 2019 with data from the Brazilian Institute of Geography and Statistics (IBGE) for São Paulo State’s municipalities. Findings From 1999 to 2019 there were movements in both directions, but an overall trend towards specialization. Clusters were statistically significant, moved throughout the state and outliers became more frequent, suggesting a weakening of spatial dependency concerning patterns of diversification or specialization. Research limitations/implications The research does not evaluate drivers of diversification or specialization. Future research should include explanatory variables to assess progress toward SDG 2.4. Social implications Specialization in agriculture can reduce crop diversity, impacting food security and resilience against climate change. Advocating for diversification supports sustainable food systems and community well-being. Originality/value It proposes using the SDI' as a metric for SDG 2.4 and provides insights into agricultural trends in São Paulo, emphasizing the importance of diversification in sustainable agriculture.