Forms and functions of bridging factors: specifying the dynamic links between outer and inner contexts during implementation and sustainment

BACKGROUND: Bridging factors are relational ties, formal arrangements, and processes that connect outer system and inner organizational contexts. They may be critical drivers of evidence-based practice (EBP) implementation and sustainment. Yet, the complex interplay between outer and inner contexts is often not considered. Bridging factors were recently defined in the updated Exploration, Preparation, Implementation, Sustainment (EPIS) framework. Further identification and specification of this construct will advance implementation models, measures, and methods. Our goal is to advance bridging factor research by identifying relevant dimensions and exemplifying these dimensions through illustrative case studies. METHODS: We used a multiple case study design. Each case (n = 10) represented different contexts, EBPs, and bridging factor types. Inclusion criteria were the presence of clearly distinguishable outer and inner contexts, identifiable bridging factor, sufficient information to describe how the bridging factor affected implementation, and variation from other cases. We used an iterative qualitative inquiry process to develop and refine a list of dimensions. Case data were entered into a matrix. Dimensions comprised the rows and case details comprised the columns. After a review of all cases, we collectively considered and independently coded each dimension as function or form. RESULTS: We drew upon the concepts of functions and forms, a distinction originally proposed in the complex health intervention literature. Function dimensions help define the bridging factor and illustrate its purpose as it relates to EBP implementation. Form dimensions describe the specific structures and activities that illustrate why and how the bridging factor has been customized to a local implementation experience. Function dimensions can help researchers and practitioners identify the presence and purpose of bridging factors, whereas form dimensions can help us understand how the bridging factor may be designed or modified to support EBP implementation in a specific context. We propose five function and three form bridging factor dimensions. CONCLUSIONS: Bridging factors are described in many implementation models and studies, but without explicit reference or investigation. Bridging factors are an understudied and critical construct that requires further attention to facilitate implementation research and practice. We present specific recommendations for a bridging factors research agenda. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13012-021-01099-y.