“It's not just about the numbers”: Inside the black box of nurses' professional judgement in nurse staffing systems in England and Wales: Insights from a qualitative cross-case comparative study

Whether implicit or explicit, professional judgement is a central component of the many nurse staffing systems implemented in high-income countries to inform workforce planning and staff deployment. Whilst a substantial body of research has evaluated the technical and operational elements of nurse staffing systems, no studies have systematically examined the role of professional judgement and its contribution to decision-making.To explore nurses' use of professional judgement in nurse staffing systems in England and Wales.A cross-case comparative design centred on adult in-patient services in three University Health Boards in Wales and three National Health Service Trusts in England. Data generation was undertaken between January 2021 and March 2023 through stakeholder interviews, observations of staffing meetings, and analysis of documents and artefacts. Observations were undertaken in clinical areas but limited to three cases by COVID-19 restrictions. Analysis was informed by translational mobilisation theory.Two kinds of professional judgement were deployed in the nurse staffing systems: the judgement of clinical nurses and the judgement of senior nurse managers. The research highlighted the reflexive relationship between professional judgement and data, and the circumstances in which organisations placed trust in people and when they placed trust in numbers. Nurses' professional judgement was central to the generation of data, its interpretation and contextualisation. Healthcare organisations relied on the professional judgements of clinical nurses and senior nurse managers in making operational decisions to mitigate risk, where real-world understanding of the status of the organisation was privileged over formal data. Professional judgement had attenuated authority for the purposes of workforce planning, where data was a master actor. Nurses expressed concerns that strategic decision-making prioritised safety and efficiency, and formal measurement systems did not capture important aspects of care quality or staff wellbeing, which made it difficult to articulate their professional judgement.The implementation of staffing systems is resource intensive. Given limited evidence on which to recommend any specific methodology, the priority for future research is to optimise existing systems. If nurses are to deploy their professional judgement to proactively influence the conditions for care, as well as responding to the challenges of risk mitigation, there is a need for robust systems of nursing measurement aligned with agreed standards of care and a vocabulary through which these judgements can be articulated.Health systems depend on nurses' professional judgement for operational staffing decisions, but data is privileged over professional judgement for workforce planning.