A new sustainability model for measuring changes in power and access in global commodity chains: through a smallholder lensHigh-value agricultural commodities face substantial economic, environmental and social sustainability challenges. As a result, commodity industries are adopting sustainable supply- and value-chain models to make production more efficient, traceable and risk-averse. These top-down models often focus on giving higher prices to smallholder producers. While an important component of sustainability, this focus on farm-gate prices has shown mixed results in part because they are less effective in highlighting the asymmetrical power relationships and the socio-economic and ecological complexity in high-value commodity production. Here, we use a novel method to measure and visualise changes in smallholder power in Madagascar’s northeast ‘vanilla triangle’—home to about 80% of the world’s high quality vanilla. Our results reveal the paradox that during the recent price surge an overall increase in smallholders’ multi-dimensional power to access economic benefits was accompanied by a decrease in many other equally important measures of sustainability. This illustrates how effective models for understanding global sustainable commodity chains should incorporate smallholders' perspectives that often emphasise complexity and uncertainty, and which aims to increase power and access for producers across both high and low price points.