This PowerPoint presentation from the AEA 2014 conference in Denver on 17 October 2014 compares monitoring and evaluation of two health interventions going to scale in complex systems - one a public sector health system in Rwanda, the other a community-based system in Benin. Still a work-in-progress, scale up of a community-based health intervention approach required defining complex community system boundaries, reaching different stakeholders, defining a new set of outcome variables (tipping points of sustainability within complex systems), and sometimes different monitoring and evaluation approaches to measure scale-up processes and outcomes.