Le jeudi 22 octobre 2009, à 13 h 30, à la salle 1240 du pavillon Alexandre-Vachon.
Cultural Imagery and Statistical Models of the Force of Mortality.
Par James Hanley, McGill University.
I will begin with the history of the term « hazard function » and its actuarial forerunner « force of mortality. » I will then describe selected artistic and scientific depictions of the force of mortality (hazard function, mortality rate), a concept that has long pre?occupied actuaries and statisticians. The « Bridge of Human Life » (Addison, 1711) provides a particularly vivid image, with the forces depicted as external. The model used by Gompertz (1825) appears to treat the forces as internal. « The Chances of Death » (Pearson, 1897) mathematically « modernizes » the medieval conception of the relation between Death and Chance by decomposing the full mortality curve into ?ve distributions along the age axis, the results of ?ve « marksmen » aiming at the human mass crossing this bridge. I will describe the imagery, critique Pearson’s statistical model, and give the Bridge of Life a modern form, illustrating it via statistical animation.?I will also describe how the epidemiologic concept of a « person-year » was viewed by an influential but little-known actuary who was a contemporary of Gompertz. This work is joint with Elizabeth Turner, a Research Fellow in Medical Statistics at the London School of Hygiene & Tropical Medicine.