What counts as a core intervention component? Developing the Core-FAST (Fidelity and Adaptation for Scaling up Tool)...

While fidelity is a significant implementation outcome, the balance with adaptation has gained prominence when scaling up evidence-based interventions, to ensure equity in meeting local community needs within the resources available. Before undertaking adaptation of an evidence-based intervention, many fidelity/adaptation frameworks concur with the need to identify intervention 'core components' to facilitate replication. However, how to do this less clear. By creating a 'plug-in' tool, we sought to add value to existing theories, models and frameworks. The aim of this study was to co-design a plug-in tool - Core-FAST (Fidelity and Adaptation for Scaling up Tool)-to facilitate identification of core components when scaling up cancer care.

We employed a sequential, exploratory, multi-phase qualitative study in the context of cancer care to elicit in-depth perspectives from different collaborator groups: informed consumers (n = 10); cancer clinicians (n = 11); and implementation researchers (n = 11). Following a review of the literature, we used an inductive approach with two sequential activities: 1. Online workshops followed by 2. Tool development and review of Core-FAST. We employed inductive content analysis.

Eight themes were identified from the workshops ranging from core components to warranted variations of these components: 1)Establishing the implementation context; 2) Retaining active ingredients; 3) Patient safety; 4) Compliance with regulatory frameworks; 5) Alignment with organizations policy and regulatory frameworks; 6) Compatibility with local infrastructure; 7) Equity and; 8) Acceptability. A draft version of Core-FAST was developed and following review, the final version comprised of seven questions to ask of each intervention component to identify core components and those open to adaptation.

Core-FAST proposes a pro-active method to prospectively identify which intervention components are non-negotiable, and must be retained, and those amenable to change, to support the equitable scale up and replication of evidence-based interventions. Future research is required to evaluate the extent to which Core-FAST enables efficient adaptation and identification of impact on intervention outcomes. The feasibility of applying Core-FAST to support decision-making should be investigated in further work including the co-design of an accessible version e.g., digital for use in practice.