In the Intensive Care Unit, clinicians are continuously faced with the difficult task of prognosis, but their predictions of patient survival status may not always be consistent. Specifically very little is known about consistency of predictions over time. The aim of this paper is to assess the consistency of nurses' daily predictions of survival in terms of inter-observer variance and variance of observers over time. We found a low consistency of these predictions between observers and over time, even though changes in the patients' condition are considered. Our findings have implications to the process of end-of-life decision-making, which pertains to withholding or withdrawing intensive care treatment.