This document discusses the importance of collecting and analyzing sex-disaggregated data. It provides examples from Mongolia of how collecting data separately for women and men can help identify issues, inform policymaking, and evaluate programs. Specifically, studies of coal transporting truck drivers and female service providers along transportation corridors in Mongolia used sex-disaggregated data to find higher risk behaviors among certain groups and influence factors like education levels and access to health information. The document also outlines challenges to collecting and using sex-disaggregated data, such as reluctance to see it as relevant, lack of capacity and resources, and insufficient use of data in policymaking.