The early warning score system is a decision-making tool that has a simple design, yet its implementation in healthcare organisations is proving complex. This article reports the results of a survey that evaluated nurses’ experiences of using the National Early Warning Score (NEWS) in an acute hospital in Ireland. Staff reported that the NEWS was easy to use, did not increase workload and enhanced their ability to identify deteriorating patients. However, they also identified problems related to doctors’ delayed response times, doctors’ lack of training in the use of the tool, and a failure by doctors to modify trigger parameters for patients with chronic conditions. NEWS enhances nurses’ roles in early detection of patient deterioration, but delays in response times by doctors expose systematic flaws in health care. This suggests that it is not only an indicator of patient deterioration, but also of deteriorating healthcare systems.