Abstract
AIMS: This study aimed to psychometrically test the instrument "Complexity of Nursing Care" and to broaden the understanding of the instrument's psychometrics and applicability. DESIGN: Embedded mixed-methods design. METHODS: We performed a cross-sectional study assessing all stationary patients of five Swiss hospitals daily for up to 5 days with the instrument "Complexity of Nursing Care" over a 1-month period in 2015. The scale's psychometrics were analysed using partial least square structural equation modelling. In the qualitative study section, we completed 12 case studies and analysed them case-wise and across cases. Quantitative and qualitative results were synthesized in tables. RESULTS: Structural equation modelling confirmed a reflective-formative second-order model of the instrument with good psychometric properties leading to a formula for the calculation of a complexity score. Qualitative results evolved descriptions of low and high extent of complexity. Narrative considerations of two raters deepened the understanding of the inter-rater reliability.