Key Points Question What is the discriminative accuracy of physicians and nurses in predicting 6-month mortality and functional outcomes of critically ill patients? Findings In this prospective cohort study of 303 critically ill patients, physicians most accurately predicted 6-month mortality (positive likelihood ratio, 5.91; negative likelihood ratio, 0.41) and least accurately predicted cognition (positive likelihood ratio, 2.36; negative likelihood ratio, 0.75).