Performance of the Safer Nursing Care Tool to measure nurse staffing requirements in acute hospitals: a multi-centre observational study

Objectives: To determine the precision of nurse staffing establishments estimated using the SNCT patient classification system, and to assess whether the recommended staff levels correspond with professional judgements of adequate staffing. Setting / population 81 medical/surgical units in 4 acute care hospitals. Methods: Nurses assessed patients using the SNCT and reported on the adequacy of staffing at least daily for one year. Bootstrap samples of varying sizes were used to estimate the precision of the tool’s recommendations for the number of nurses to employ on each unit. Multi-level regression models were used to assess the association between shortfalls from the measured staffing requirement and nurses’ assessments of adequate staffing. Results: The recommended minimum sample of 20 days allowed the required number to employ to be estimated with a mean precision of 4.1%. For most units, much larger samples were required to estimate establishments within +/- 1 whole time staff member. Every registered nurse hour per patient day shortfall in staffing was associated with an 11% decrease in the odds of nurses reporting that there were enough staff to provide quality care and a 14% increase in the odds of reporting that necessary nursing care was left undone. No threshold indicating an optimal staffing level was observed. Surgical specialty, patient turnover and more single bedded rooms were associated with lower odds of staffing adequacy. Conclusions: The SNCT can provide reliable estimates of the number of nurses to employ on a unit, but larger samples than the recommended minimum are usually required. The SNCT provides a measure of nursing workload that correlates with professional judgements, but the recommended staffing levels may not be optimal. Some sources of systematic variations in staffing requirements for some units are not accounted for. SNCT measurements are a potentially useful adjunct to professional judgement, but cannot replace it.Peer reviewe