In 2019, San Patten was presented with an opportunity to co-run an independent external Expert Advisory Committee on Evaluation for UNAIDS. The UNAIDS Programme Coordinating Board had approved the establishment of an independent evaluation function reporting directly to the UNAIDS Board. The function would comprise evaluation experts appointed by Member States, civil society, and UNAIDS Sponsors. Patten was nominated by the NGO Delegation to represent civil society in the committee. This seemed like a natural progression of Patten’s career, as she had been working in the field of HIV/AIDS for more than two decades at that point. 

In early June, UNAIDS convened the first meeting of the Measurement and Evaluation Reference Group’s (MERG) Indicator Working Group. The purpose of the MERG is, as its name indicates, to measure and evaluate the performance of the UNAIDS Programme around the globe. The MERG currently tracks some 150 indicators of countries’ efforts to address the AIDS pandemic.