The case studies were developed based on a common terms of reference that sought to identify similarities among countries as well as distinct or unique challenges and opportunities in a way that supports appropriate policy responses. The five case studies were developed by regional experts. The Ecuador study was developed first as an example to guide the others. The experts were selected by a process similar to that of the overall project proposal (a public call for expression of interest through the UNEP website and the mercury partnership list). The Mongolia case study was developed through an in-kind contribution from the Sustainable Artisanal Mining (SAM) project