Scoping implementation science for the beginner: locating yourself on the “subway line” of translational research

BACKGROUND: Beginners to the discipline of implementation science often struggle to determine whether their research questions “count” as implementation science. MAIN TEXT: In this paper, three implementation scientists share a heuristic tool to help investigators determine where their research questions fall in the translational research continuum. They use a “subway model” that envisions a journey to implementation research with stops along the way at efficacy and effectiveness research. CONCLUSIONS: A series of structured questions about intervention efficacy, effectiveness, and implementation can help guide researchers to select research questions and appropriate study designs along the spectrum of translational research.