Longevity Research Initiative · Actuarial Note

Life Expectancy Shift Calculator

Cohort-mean effect of extending lifespan for a covered subset of deaths above a cutoff age, anchored to the U.S. Social Security Administration 2022 Period Life Table (2025 Trustees Report).

Baseline life expectancy 78.0 yr

Cutoff age (deaths above this age) 20

Coverage of over-cutoff deaths 91%

Per-beneficiary life gain 7.9 yr

Population basis

Anchor baseline to SSA e₀ by sex (74.7 M / 80.2 F / 78 blend)

New life expectancy at birth

85.11 yr

Change of +7.11 years from a 78.0-year baseline.

Decomposition
Survival to cutoff, S(a)	0.98891
Coverage	0.910
Beneficiary share of cohort	0.8999
Cohort-mean shift	+7.109

Antithesis — read before citing

This applies the gain as a uniform additive shift to each beneficiary's age at death. That is generous at advanced ages, where competing mortality is severe (male q₉₅ ≈ 0.28); a mechanistically faithful estimate would instead modify the age-specific mortality rates qₓ (e.g., via a cause-specific hazard ratio) and re-derive the table, yielding a smaller, age-localized gain. The figure above is valid if the stated gain already represents a net, competing-risk-adjusted per-person extension.

Survival table excerpt

SSA 2022 period life table — survivors per 100,000 born
Exact age	Male lₓ	Female lₓ	Blended S(a)

Source: U.S. Social Security Administration, Period Life Table 2022 (2025 Trustees Report) · ssa.gov/oact/STATS/table4c6.html
Blended basis weights male:female births at 105:100. Life expectancy at birth = mean age at death across the cohort; a uniform per-beneficiary gain shifts that mean by gain × beneficiary share.