Among the scary numbers in the Intergenerational Report was the estimate that, by 2050, life expectancy would have risen to 95/96 years, which would seem to imply a huge increase in the number of years spent in retirement. I checked and found that the report gave current life expectancy as 92/93 years, far higher than the 80 or so that is usually quoted. The reason, it turns out is that the standard estimate is done on a “period” basis, using the age-specific mortality rates of the present. The higher estimate is done on a “cohort” basis, taking account of expected future reductions in mortality. More on this here.
A few observations on this point.
* An increase of four years is neither surprising nor alarming. This is doubtless why this comparison ins not made in the IGR.
* In my last post, I noted the use of the obsolete 15-64 category to estimate the working-age population. One possible defence was that this was done in consistency with past practice. But clearly this can’t apply to the (unannounced) shift from the standard period basis to a cohort basis
* More importantly, the 95-year figure is an estimate of the likely life expectancy of children born in 2050, who would reach retiring age some time after 2115. Even the current birth cohort won’t be of pensionable age until near the end of this century.
A cohort measure of life expectancy is more relevant to projections of future pension expenditure than a period measure, though it requires the use of estimates of future mortality. But the relevant cohorts for the purpose of the IGR are those born before 1983 who will be 67 and over in 2050 and will then (assuming no policy change) be eligible for the age pension.