2.6 Edmund Halley - comet and life expectancy

In the early years of population research the main focus of study was on mortality - which is quite easy to understand in view of the fact that death was very much an everyday occurrence in those days. Mortality among newborn children was high and epidemics frequently took a toll on the population. Lists of deaths increased people's interest in these phenomena even further.

Edmund Halley (1656-1742) became famous for discovering the comet that today bears his name. Besides making several astronomic and geographic observations and calculations, Halley examined lists of deaths in Bleslau (the present Polish town of Wroclaw). These lists were more complete than those used in London at the time as they also indicated the age and gender of the deceased person. Based on this material, Halley calculated life expectancies using age group specific mortality rates for the first time ever. At the time the life expectancy of a newborn baby was just 30 years!