Driven by evidence of continuing gaps in health care quality and efficiency and inspired by the emergence of new value-based payment models, both large and small health care organizations are developing and deploying a wide range of care delivery innovations. But how can decision makers in these organizations determine if the innovations really improve service delivery, patient experience, clinical outcomes, or costs? Organization leaders need appropriate, timely evidence to inform their decision making. In this article we describe a range of approaches to evaluating innovations and pose key questions about the validity of the results. We highlight a specific type of evaluation approach—the stepped wedge design—because it can balance the need for internal and external validity with the ability to generate timely results. We elaborate on three key steps in the innovation assessment phase (identifying the target population, describing baseline performance, and documenting the components of the innovation) that are useful for both organizations that will generate new evidence and those using evidence generated by others. We conclude with a discussion of payer approaches for supporting health care organizations in their efforts to develop new evidence on innovations.