SummaryMortality is a good measure of killing, but it is a poor measure of cure, palliation or the maintenance of function. Nevertheless, it has remained the primary metric of hospital care for 200 years. This article discusses the factors that contribute to mortality risk and survival trajectories, as well as the increasing recognition that surgery kills for months after the last suture is tied. This article discusses how disparate factors can usefully combine to generate an 'elderly' group with a monthly mortality in excess of 1% and a median life expectancy less than 3.5 years. A downloadable spreadsheet is provided that combines risk factors to generate mortality risks and their associated survival curves, emphasising the importance of looking beyond one postoperative month. If the function of a hospital were to kill the sick, statistical comparisons of this nature would be admissible.-Florence Nightingale, 1859 [1] Mortality is an insensitive measure of care: most patients survive the postoperative period, whilst (perhaps) many observed deaths are not associated with poor care. We should concentrate on the living, not the dead. Unfortunately, information on the effect surgery has on people's lives is scarce, in comparison with how often it kills them. This paper discusses how to estimate the chance that someone will die and how much this might change following surgery, but in so doing, we might reflect on Florence Nightingale's observation that mortality is an excellent measure of performance only for those trying to kill. Chance (at least in part) determines survival and death, which can be estimated using certain characteristics throughout adulthood: age; sex; historical morbidity; and physiological function [2][3][4][5][6][7][8][9][10][11][12]. The latter two characteristics are meant in their broadest sense, so that together they might accommodate variables that are, or might be, independently associated with survival. For instance, socioeconomic status is an historical characteristic that confers morbidity and mortality risks, whereas brain natriuretic peptide (BNP) is a marker of physiological function that might be shown to have an independent prognostic value. Crucially, variables used in the calculation should have a known independent effect on long-term survival in the general, non-surgical population, so that all the purposes of pre-operative mortality estimation are served (see below). Variables, such as BNP, have yet to declare their value in promoting the precision of perioperative prognostication, because their relationship with general survival has been inadequately described.It is one's risk of death, rather than one's proximity to birth, that determines the trajectory of one's remain-