It’s unclear whether Auguste Comte really said that “demography is destiny,” but you can and should use demographic data to make better estate and financial planning decisions.
As we’ve noted, an estate plan often represents a set of predictions about a family’s future, predictions that will be improved when the plan considers the family’s Longevity Distribution. Your family has one, it’s unique, and your planning should reflect it.
Demographers and actuaries at the Social Security Administration collect and summarize data on lifespan probabilities. The SSA data assumes a cohort of 100,000 people, and tracks how the cohort will grow smaller over time. By the time male cohort members are about age 80, half of them are projected to be living. For the female cohort, the halfway mark is around age 84. Those male and female halfway marks are the government’s best life expectancy estimates.
I think the distribution of lifespan reflected in the cohorts is much more useful for planning by clients and advisors than a single life expectancy point estimate.
If a financial and estate plan relies on point life expectancy estimates, those estimates are almost certain to be wrong, because half of the cohort members will live less, and half will live longer, than their life expectancy. A robust plan should work well across a wide range of longevity spans for various family members.
I used the SSA cohort data to make sample Longevity Distributions for two different families.