Abstract
<title>Abstract</title> <p>Background Implementation failure is inconsistently defined and conceptually underdeveloped in the implementation science (IS) literature. This impedes implementation research, practice and learning opportunities. To address these ambiguities, we conducted a scoping review of how health-related IS literature conceptualizes implementation failure. Methods Eleven databases were searched. Studies were selected based on predefined eligibility criteria; relevant data were extracted and coded by two reviewers, using a codebook based on a modified version of the Consolidated Framework for Implementation Research. To develop themes, we used regular meetings to interpret emerging patterns, refine conceptual boundaries and strengthen the theoretical and policy relevance of the analysis. Results We found four themes relating to the context and recurring determinants of failure: 1) failures in the implementation environment, 2) gaps in implementation planning, 3) inadequate individual capability, opportunity, and motivation and 4) failure to achieve and sustain innovation-context fit. We also analyzed how failure manifests across various implementation phases, a cross-cutting theme of power and equity and conceptual relationships. Across the literature, we found “implementation failure” used without clear definitions or measurement and a conflation of implementation and innovation failure. We defined implementation failure as a gap between the aspirations and outcomes of a specific implementation process, encompassing the failure to deliver benefits of evidence-based practices to the people and communities that deserve to share in the benefits of research. Discussion Implementation failure remains conceptually ambiguous within the IS literature. The IS field must adopt clearer, more rigorous terminology to distinguish contextual challenges from outright failure. While examining failure yields insights obscured by a focus on success, we note a paradox that naming failure may individualize blame or treat ongoing adaptation as deficient. To support implementation success and promote learning, we present 1) an Implementation Failure Assessment Guide and 2) recommendations for implementation research, practice and support. Conclusion Our synthesis delivers a nuanced conceptualization of implementation failure. The value of examining failure lies in identifying where, for whom, and from whose perspective an implementation process fell short. Prioritizing the study of failure offers opportunities for learning and optimizing vital resources to accelerate implementation and ensure sustainment.</p>