The promise of adaptation and adaptive designs in implementation science has been hindered by the lack of clarity and precision in defining what it means to adapt, especially regarding the distinction between adaptive study designs and adaptive implementation strategies. To ensure a common language for science and practice, authors reviewed the implementation science literature and found that the term adaptive was used to describe interventions, implementation strategies, and trial designs. To provide clarity and offer recommendations for reporting and strengthening study design, we propose a taxonomy that describes fixed versus adaptive implementation strategies and implementation trial designs. To improve impact, (a) futureimplementation studies should prespecify implementation strategy core functions that in turn can be taught to and replicated by health system/community partners, (b) funders should support exploratory studies that refine and specify implementation strategies, and (c) investigators should systematically address design requirements and ethical considerations (e.g., randomization, blinding/masking) with health system/community partners.
Keywords: adaptation; cluster randomized design; community engagement; implementation strategies; quality improvement.