Natalie Leon is a specialist scientist who focusses on two key research strategies to contribute health systems evidence: process evaluations alongside complex interventions and evidence synthesis. Her process evaluation research findings have shown the importance of the health system context in shaping outcomes in a range of service delivery areas studied, including testing the effectiveness of provider-initiated HIV testing, analysing development of rapid diagnostics for MDR-TB, the UNICEF Integrated Health System Strengthening (IHSS) programme and evaluation of scalability of innovative mHealth care for community-based and chronic care. Her evidence synthesis research includes quantitative systematic reviews of routine health information and relatively new qualitative synthesis methods (task shifting for safe home-based abortion care and mHealth care). She is currently leading a multi-country, multi-stage process evaluation of a mHealth, text message-based randomised controlled trial for adherence to diabetes care and is co-investigator for an innovative study aimed at harnessing routine health information for facility and community-based collaboration on increasing linkage to HIV care for men. She is an Honorary Assistant Professor at Brown University USA.