Tannis examines food retailers and manufacturers' role in improving social and environmental outcomes in their agricultural supply chains. Her current work includes a collaboration with Woolworths, a high-end food retailer based in South Africa, to understand the impact of Woolworths’ private standard program in influencing the uptake of environmental management practices at the farm level. Tannis has also conducted a large-scale study of 450 companies’ sustainable sourcing practices in the food, textile and wood-products sector. Her research also examines the opportunities and challenges for the chocolate industry to improve the sustainability of the cocoa supply chain. Prior to Stanford, Tannis worked as an Investment Analyst at an impact-investing firm focused on sustainable agriculture and forestry. She has also spent time doing field research with smallholder farmers in Kenya, consulting on social and environmental issues for a large-scale soybean firm and for the agriculture technology non-profit Digital Green. Tannis received her BA in Environmental Science and Public Policy from Harvard University. In her free time Tannis enjoys cross-country skiing, surfing and backpacking in the mountains of California and Washington State.