Driven by policy, shaped by context: a complexity-informed multiple case study of the six-month review for stroke survivors

<title>Abstract</title> <bold>Background:</bold> The six-month review is a policy recommendation in the United Kingdom aimed at identifying and addressing the unmet needs of stroke survivors. Differences in the provision of this complex intervention may arise from variations in context. Our study aimed to explore the dynamic interaction between the six-month review and its associated context. <bold>Methods:</bold> A qualitative multiple case study was conducted across three contrasting six-month review services in England selected primarily to reflect variation in provider organisation. Data collection included semi-structured interviews with three stakeholder groups ( <italic>Service Users, Service Providers,</italic> and <italic>Service Influencers</italic> ) <italic>,</italic> direct observations of the review process, and service-related documents. Data analysis utilised a combined deductive and inductive approach. Using the Context and Implementation of Complex Interventions framework, contextual interactions were mapped at the micro, meso and macro levels across the three cases. A cross-case synthesis, guided by complexity theory, identified key patterns of interaction between the six-month review and its context, which were summarised narratively. <bold>Results:</bold> Data were collected from 36 stakeholders, 17 hours of observation, and 26 service-related documents. <bold/> Five key patterns of interaction between the six-month review and its context were identified: (1) Access is a dynamic negotiation between service design and contextual barriers, (2) Equitable service provision requires proactive adaptation , (3) Hidden needs stay hidden unless actively unmasked, (4) System levers may trigger unpredictable consequences, and (5) Outcomes are shaped by interdependence with the wider system. <bold>Conclusions:</bold> The findings demonstrate the multi-level influence that context has on the implementation and delivery of the six-month review. These contextual interactions shape outcomes in varied, unpredictable, and sometimes unintended ways, reflecting the six-month review’s position within a complex system. The identified patterns of interaction provide insight into the six-month review’s underlying mechanisms and may guide future implementation efforts.