Food Prices for Nutrition project develops tools and conducts research to help programmers and policymakers access and use food price and diet cost data to design more effective food systems policies and programs for nutrition. You can access a range of publications and other resources on their website to learn about metrics and how they can be used. Their project aims to support governments, international organizations, educational institutions, and civil society organizations in using of new metrics, accessing a global system to monitor change in food prices for nutrition, and analyzing changes in cost and affordability of healthy diets.