Life tables
What Is a Life Table?
A life table is a structured way to summarize how mortality changes with age. It is one of the main tools behind life expectancy estimates.
What a life table contains
A full life table usually includes the probability of dying at each age, the number of survivors from a starting population, deaths during the year, person-years lived, and remaining life expectancy.
Most people only see the final remaining-life column, but that number comes from the full age-by-age structure.
Why life tables are useful
Life tables help governments, insurers, researchers, and households understand population averages. They are used in Social Security projections, public health reports, annuity pricing, and planning discussions.
They are especially useful because they separate life expectancy by exact age. A 65-year-old's remaining expectancy is not the same as life expectancy at birth.
What they cannot see
A standard life table does not know your current health, habits, medical care, family history, occupation, wealth, or risk tolerance. It is a clean population average, not a personal profile.
That limitation is also what makes life tables easy to use responsibly: they are good for broad perspective and weak for personal prophecy.