Practical application of hybrid effectiveness–implementation studies for intervention research

Hybrid effectiveness–implementation studies have emerged to address design challenges that researchers face when assessing evidence-based intervention implementation in real-world settings. Hybrid studies maximize the usefulness of effectiveness studies by allowing both effectiveness and implementation research questions to be included in the same study, regardless of the research design (observational, individually randomized trials, cluster-randomized trials, preference designs, adaptive designs, etc). Hybrid studies utilize implementation science methods to facilitate integration of research findings into public health programming, health-care practice, and community and policy settings. In this article, we describe the three types of hybrid studies, which exist on a continuum depending on the emphasis placed on the effectiveness vs the implementation research questions. We discuss common implementation outcomes with examples of how the stage (or phase) of implementation can influence selection of implementation outcomes. We then summarize hybrid study examples from recent literature and present practical considerations when designing a hybrid study. Finally, we outline examples of implementation-focused research questions to consider asking by phase of implementation and discuss related sampling approaches.