ABSTRACT Objective Peer review is a widely used mechanism to support quality improvement in healthcare, yet its effectiveness remains uncertain. This study aims to examine how peer review visits contribute to care quality improvement in NHS England's specialised commissioned services, and to develop a theory of change that explains their mechanisms of action. Methods A theory‐based evaluation was undertaken using qualitative methods. Data were collected in two phases: (1) 17 semi‐structured interviews with peer reviewers, NHS staff, commissioners, and patient representatives; and (2) two stakeholder workshops with directors of nursing and service commissioners. Thematic analysis using deductive coding was guided by the Impact Domain Framework. Findings were synthesised into a logic model and Theory of Change, visualised using Directed Acyclic Graphs (DAGs), incorporating relational dimensions of peer review. Results Analysis of transcripts from a diverse range of stakeholders produced four core themes: the tension between compliance and learning objectives; the role of trust and relational dynamics; limited mechanisms for knowledge exchange; and a lack of follow‐up impeding sustained improvement. The final Theory of Change model distinguishes between compliance‐driven and learning‐driven pathways, integrating relational factors such as trust and engagement as key enablers of improvement. Conclusion Peer review visits are more effective when perceived as opportunities for learning rather than compliance monitoring. The study offers a novel Theory of Change and visual model to guide future evaluation and practice, emphasising the importance of relational dynamics and sustained follow‐up. These insights should inform both implementation and policy by supporting a shift toward trust‐based, developmental peer review models that strengthen organisational learning and align with the goals of a learning health system.
Kaehne et al. (Sun,) studied this question.