Optimising Nursing Management: Development of a Tool to Determine Span of Control and Resource Needs of First-Line Nurse Managers in Spanish Hospitals—A Mixed-Methods Study

<b>Background</b>: First-Line Nurse Managers (FLNMs) have been recognised as key contributors to achieving organisational objectives, serving as vital intermediaries between management, staff, and patients. Assessing whether the Span of Control (SOC) is appropriate and providing the necessary support for FLNMs to fulfil their responsibilities poses a considerable challenge for healthcare organisations. No tool exists in Spain to guide decisions regarding FLNM's SOC and resource needs. The aim of this study is to design a tool for assessing the span of control of first-line nurse managers in hospitals. <b>Methods</b>: This study employed a tool development and content validation design to create the EASOC-Nursing instrument (Eliges Aragón SOC tool). The study was conducted in three stages: an integrative literature review, followed by a national Delphi study with 43 experts in nursing management, and finally, focus group discussions. <b>Results</b>: A tool was created to assess first-line nurse managers' (FLNM) span of control (SOC) using 13 key indicators, organised into four categories: unit (operations and resources, conflicts, and logging and monitoring of activities), professional (staff and competencies), FLNM (autonomy, education, and leadership), and organisation (support systems, education, and research). It includes a total of 31 items and determines SOC adequacy by establishing cut-off points that classify it as below acceptable, appropriate, or excessive. When the SOC is inadequate, the tool provides specific recommendations for support measures, such as the provision of administrative personnel or the appointment of a co-leader. <b>Conclusions</b>: The EASOC-Nursing tool offers a comprehensive evaluation of the core dimensions of the FLNM role and its responsibilities in Spain. Furthermore, it delivers practical guidance on the most suitable types of support to facilitate the attainment of optimal outcomes for both patients and healthcare organisations. In light of the global nursing shortage, the availability of a robust and context-sensitive instrument to assess the SOC enables hospital nursing management to allocate resources more strategically, thereby enhancing working conditions for professionals and contributing to improved patient care outcomes.