The remarkable success of the Keystone ICU project was initially publicized as an example of the power of checklists. While checklists are a useful safety tool, this study used an ethnographic approach to better understand the sociological factors that helped the project succeed. The authors highlight the densely networked community, the multimodal interventions, the data-driven processes, and the reframing of catheter-related blood stream infections as a social problem as important contextual factors that must be considered in quality improvement efforts. These lessons are especially important given that subsequent studies have found difficulty in implementing checklists in the absence of a robust safety culture.