A taxonomy of the process in implementation science: the Global Impact Analytics Framework (GIAF)

BACKGROUND: Despite growing global efforts to evaluate the impact of research, there remains a lack of practical, standardised tools to assess implementation in the real-world.

AIM: This study introduces a comprehensive implementation taxonomy for use in impact evaluations based on onto-terminology principles.

METHODS: This work is part of the Global Impact Analytics Framework (GIAF) program. An international expert panel of 32 members developed the taxonomy using nominal group techniques and an iterative refinement process. The design was informed by the Technology Readiness Levels for Implementation Sciences (TRL-IS) to ensure its relevance and application across the life cycle of implementation. Case studies have been conducted in ten countries and the knowledge gained from practical experiences has been incorporated into the taxonomy.

RESULTS: The GIAF taxonomy outlines 82 subdomains organised across 15 domains and three sequential implementation phases. The Initiation phase captures early preparatory steps before real-world use, including planning, engagement, and pre-readiness. The Maturity phase focuses on early implementation and real-world demonstration studies, covering the initiative's readiness (from demonstration to release), dissemination, usability, adoption, and uptake. The Evolution phase refers to later-stage activities once the intervention or tool is fully implemented, with domains encompassing sustainability, diffusion, prolongation, expansion, diversification, exporting, and de-implementation. The taxonomy is supported by tools including a glossary and practical checklists to guide consistent application.

CONCLUSIONS: The GIAF taxonomy offers a structured, detailed, and flexible toolkit for evaluating implementation processes using mixed methods and across diverse projects and settings. It supports both quantitative scoring and qualitative insight to inform cross-context comparison and learning. By clearly defining and measuring these processes, it enhances the rigour, replicability, and comparability of implementation research and practice. The taxonomy also supports comparative effectiveness analyses of implementation strategies. This comprehensive approach addresses a critical gap in the implementation science field, contributing to stronger evidence-based practices, health and social care programs, and research globally. The GIAF toolkit provides researchers, evaluators, and other decision-makers with a practical resource for assessing implementation impact. It can also support planning processes and, through learnings from assessment results, help improve future implementation efforts.