Implementation research and delivery science (IRDS) is a process to both understand “what’ works and “how” to get what works to the populations that need it to improve health outcomes. The process has been called by many names (e.g. implementation research, implementation science), is closely related to other approaches (e.g. operations research), and is an integral component of health systems research. The term IRDS has recently been coined to capture both the research and delivery aspects of the process, highlighting the challenges of actually implementing and scaling up evidence-based approaches to improve health care.