Importantly, the guidelines indicate that there is no single staff-to-patient ratio that can be applied across all wards. Therefore, they advise that a range of factors need to be rigorously assessed in each ward to determine appropriate registered nurse staffing levels, using the care needs of individual patients as the main driver. Thus, an advanced level of professional judgement is needed to make an informed assessment of patient need and nursing staff requirements. Such decisions clearly need to be taken by nurses who have the ability to assess a range of indicative factors, judge the supporting evidence and use sophisticated decision-making skills to determine appropriate staffing levels. Hence, if nurses are to make safe decisions about required staffing levels, they need to be prepared appropriately and supported adequately within care provider environments.