p = 0.0003). Because of variations in the types and combinations of OSFs, associated disease, and extent of physiologic derangement, it is difficult to interpret variations in mortality among patients with one or more OSFs defined using categorical criteria. For this and other reasons, outcome prediction based on a comprehensive assessment of patient risk factors is a more sensitive, specific, useful approach to quantifying MODS than a simple count of the number and duration of OSFs. Because repeated assessment of risk factors during subsequent ICU days reflects complications and response to therapy, daily outcome predictions are even more precise than estimates at ICU admission. The ability to more accurately predict survival from MODS/MOSF can improve our ability to test new therapies, evaluate how outcome has changed over time, and assess the efficacy of supportive therapy for individuals.