Mortality tables Reading 28 vs Reading 30

In the last part of Par. of Reading 28 they clearly state that one drawback of mortality table is that it is based on an average, then there is a risk of outliving own assets.

In Reading 30 par. 31. they report the same drawback for calculations bsed on life expectancy but not for mortality tables.

It is quite confusing because mortality tables are presented as an alternative to life expectancy while, based on Reading 28 and also for common sense, they both share longevity risk.

Am I wrong?


Mortality rates are basically (# of deaths)/total lives: it works fine when you have a pool of lives, but on an individual basis, one either lives or dies.

Some people calculate PV of future earnings like a term certain that ends with life expectancy. However, if you probability weight all future cash flows ( actuarial PV), this PV is higher than the term certain approach.

Ok but in this case is PV of spending need, I understand that your reading it’s applicable in any case, but what you mean is that with mortality tables the calculation is more accurate…but in both the approach (mortality tables and life expectancy) the longevity risk applies