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Research project: Identifying nurse-staffing requirements using the Safer Nursing Care Tool. Modelling the costs and consequences of real world application to address variation in patient need on hospital wards

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In 2014 the National Institute for Health and Care Excellence (NICE) recently issued guidance on setting safe nurse staffing levels for hospitals. NICE recommended a systematic approach to setting staffing levels. NICE endorsed a tool (The Safer Nursing Care Tool or SNCT) that estimates staff requirements by assigning patients to one of five categories, based on how ill they are and the typical time taken to care for similar patients (known as acuity/dependency). The standard approach to using the SNCT sets staffing to meet the average needs of a sample of patients. There is little evidence that shows how often this means there are enough nurses on the ward to meet patient need or whether other approaches might give better results.


The Safer Nursing Care Tool is a system designed to guide decisions about nurse staffing requirements on hospital wards, in particular the number of nurses to employ (establishment). The Safer Nursing Care Tool is widely used in English hospitals but there is a lack of evidence about how effective and cost-effective nurse staffing tools are at providing the staffing levels needed for safe and quality patient care.


To determine whether or not the Safer Nursing Care Tool corresponds to professional judgement, to assess a range of options for using the Safer Nursing Care Tool and to model the costs and consequences of various ward staffing policies based on Safer Nursing Care Tool acuity/dependency measure.


This was an observational study on medical/surgical wards in four NHS hospital trusts using regression, computer simulations and economic modelling. We compared the effects and costs of a ‘high’ establishment (set to meet demand on 90% of days), the ‘standard’ (mean-based) establishment and a ‘flexible (low)’ establishment (80% of the mean) providing a core staff group that would be sufficient on days of low demand, with flexible staff re-deployed/hired to meet fluctuations in demand.


Medical/surgical wards in four NHS hospital trusts.

Main outcome measures

The main outcome measures were professional judgement of staffing adequacy and reports of omissions in care, shifts staffed more than 15% below the measured requirement, cost per patient-day and cost per life saved.

Data sources

The data sources were hospital administrative systems, staff reports and national reference costs.


In total, 81 wards participated (85% response rate), with data linking Safer Nursing Care Tool ratings and staffing levels for 26,362 wards × days (96% response rate). According to Safer Nursing Care Tool measures, 26% of all ward-days were understaffed by ≥ 15%. Nurses reported that they had enough staff to provide quality care on 78% of shifts. When using the Safer Nursing Care Tool to set establishments, on average 60 days of observation would be needed for a 95% confidence interval spanning 1 whole-time equivalent either side of the mean. Staffing levels below the daily requirement estimated using the Safer Nursing Care Tool were associated with lower odds of nurses reporting ‘enough staff for quality’ and more reports of missed nursing care. However, the relationship was effectively linear, with staffing above the recommended level associated with further improvements. In simulation experiments, ‘flexible (low)’ establishments led to high rates of understaffing and adverse outcomes, even when temporary staff were readily available. Cost savings were small when high temporary staff availability was assumed. ‘High’ establishments were associated with substantial reductions in understaffing and improved outcomes but higher costs, although, under most assumptions, the cost per life saved was considerably less than £30,000.


Understanding the effect on wards of variability of workload is important when planning staffing levels. The Safer Nursing Care Tool correlates with professional judgement but does not identify optimal staffing levels. Employing more permanent staff than recommended by the Safer Nursing Care Tool guidelines, meeting demand most days, could be cost-effective. Apparent cost savings from ‘flexible (low)’ establishments are achieved largely by below-adequate staffing. Cost savings are eroded under the conditions of high temporary staff availability that are required to make such policies function.

Project Team

PI: Professor Peter Griffiths, University of Southampton

Dr Jane Ball, University of Southampton

Dr Jeremy Jones, University of Southampton

Dr Antonello Maruotti, University of Southampton

Dr Tom Monks, University of Southampton

Dr Alex Recio Saucedo, University of Southampton

Miss Christina Saville

Ms Clare Aspden, University Hospitals Southampton NHS Trust

Ms Rosemary Chable, University Hospitals Southampton NHS Trust

Mr Andy Dimech, The Royal Marsden NHS Trust

Ms Shirley Hunter, Poole Hospitals NHS Trust

Ms Yvonne Jeffrey, Poole Hospitals NHS Trust

Ms Natalie Pattison, The Royal Marsden NHS Trust

Ms Nicola Sinden (Portsmouth Hospitals NHS Trust)

Ms Tracy Cassar (Portsmouth Hospitals NHS Trust)

Project Funder

NIHR HS&DR Programme


Associated research themes

Health Workforce & Systems

Related research groups

Health Work and Systems

Affiliate Research Group

CLAHRC Wessex Fundamental Care Theme

Conferences and events associated with this project:

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