Actuaries in life insurance and pensions make frequent use of one key demographic variable – mortality. The other two variables, fertility and migration, are not factors that most actuaries worry about in their professional lives.

This hasn’t always been the case. In 1953, for example, the Journal of the Institute of Actuaries published a paper by PR Cox entitled ‘Reproductivity in Great Britain: a new Standard of Assessment’, which began:

“Since the formation of the Demographic Study Group by the Students’ Society at the end of 1949, much attention has been devoted by a small but keenly interested body of members of the Institute to the analysis of fertility and reproductivity. One of the aims of their researches has been to arrive at an independent method of assessing the degree of sufficiency of the numbers of births in this country for the replacement of the population.”