What Is an Actuarial Life Table?
An actuarial life table — also called a mortality table — is a statistical tool that shows, for each age, the probability that a person will die before their next birthday, based on the mortality experience of a specific population. From these probabilities, life tables calculate life expectancy — the average number of remaining years a person of a given age can expect to live, assuming current mortality rates persist. Actuarial life tables are the fundamental building block of the life insurance industry, pension planning, annuity pricing, and public health policy. They transform the profound uncertainty of individual mortality into the predictable mathematics of large populations, enabling insurers to price policies, pension funds to measure liabilities, and governments to assess the long-term solvency of social security systems.
How Actuarial Life Tables Work
A life table begins with a hypothetical cohort — typically 100,000 live births. For each age, the table applies a mortality rate (qâ‚“, the probability of dying within the year) to the number surviving to that age, yielding the number of deaths. The process repeats for each subsequent age until the entire cohort has died. From this stepped simulation, the table derives: lâ‚“ — the number of people surviving to exact age x; dâ‚“ — the number dying between age x and x+1; pâ‚“ — the probability of surviving from age x to x+1; and eâ‚“ — the life expectancy at age x, calculated as the total person-years lived beyond age x divided by the number surviving to age x. Life expectancy at birth is the most commonly cited statistic, but life expectancy at older ages is arguably more relevant for retirement and insurance planning. A 65-year-old American male can expect, on average, roughly 17-18 additional years; a 65-year-old female, roughly 20-21 years. These are averages — roughly half will live longer.
Types of Life Tables and Their Applications
Different types of life tables serve different purposes. Period life tables use mortality rates from a specific time period, providing a snapshot of current mortality. They answer the question: if a person experienced today's mortality rates at each age throughout their life, what would their life expectancy be? Cohort life tables follow a specific group born in the same year, incorporating projected future mortality improvements. They are more realistic — a child born today will benefit from medical advances throughout their life that current mortality rates do not reflect — but require assumptions about the pace of future improvement. Population life tables reflect the general population and are used for public health and demographic analysis. Insured life tables are based on the experience of insured populations, who are generally healthier and wealthier than the general population (the "underwriting selection effect"), and are used for pricing life insurance and annuities. Annuitant life tables are based on the mortality experience of annuity purchasers, who tend to live longer than both the general population and life insurance purchasers — the "self-selection" of longevity. This is why the same 65-year-old might receive dramatically different life expectancy estimates from a life insurance company (which underwrites for premature death risk) than from an annuity provider (which prices for longevity risk).
Why Actuarial Life Tables Matter
Life tables translate the uncertainty of individual death into the financial mathematics that underpins trillions of dollars of insurance, pension, and social security obligations. A one-year error in estimated life expectancy at retirement can change the required pension reserve by 3-5%, translating to billions of dollars for large pension plans. Systematic underestimation of life expectancy improvements — a persistent challenge, as mortality has generally improved faster than actuarial projections anticipated — has contributed significantly to pension underfunding. The COVID-19 pandemic disrupted long-term mortality trends in ways that will take years to fully analyze and incorporate into revised tables. For individuals, understanding life expectancy — not as a prediction but as a probabilistic range — is essential for retirement planning. The most common retirement planning error is underestimating how long you will live, and therefore how long your assets must last. The concept that life expectancy is an average, with roughly half of people living longer, is one of the most important truths in financial planning.
FAQ
What is the difference between life expectancy and life span?
Life expectancy is a statistical average — the number of years a person of a given age can expect to live based on current mortality rates. Life span is the maximum possible length of life for a species — roughly 120-125 years for humans. Life expectancy has increased dramatically over the past century due to reductions in infant mortality and improvements in treating infectious and chronic diseases. Maximum life span has not meaningfully changed.
How often are actuarial life tables updated?
Major updates typically occur every decade or so, incorporating the latest mortality data and projecting future improvements. However, major events — the COVID-19 pandemic, the opioid crisis, advances in cancer treatment — can cause interim adjustments. The Society of Actuaries periodically releases updated mortality improvement scales that adjust the pace of expected future improvement, often with significant financial implications for pension and insurance reserving.
Related Terms
- Mortality Rate — the frequency of death in a defined population during a specified period
- Life Expectancy — the average number of remaining years a person is expected to live at a given age
- Underwriting — the process insurers use to evaluate risk and determine policy terms and pricing
- Annuity — a financial product providing a stream of payments for life or a specified period, priced using life tables
- Longevity Risk — the risk of outliving one's assets; the risk that actual lifespan exceeds expected lifespan
Related MoneyBestPal Guides
Use these related MoneyBestPal resources to compare Actuarial Life Table with nearby finance, economics, investing, and business concepts.
 |
| Image: Moneybestpal.com |
An actuarial life table is a table that shows the likelihood that a person will pass away before their next birthday at a certain age. Also, it displays the remaining life expectancy for persons of various ages as well as the approximate number of survivors from a hypothetical cohort of people who were born at the same time.
An actuarial life table is based on a population's mortality experience during a specific time period, typically a year or ten years. It displays the actual or anticipated trends in the mortality rates for various age categories within that population. The Social Security Administration (SSA), for instance, offers cohort life tables, which forecast future mortality rates for those born in a specific year, and period life tables, which provide life expectancy estimates for the US population based on known death rates in a particular year. These tables are used by the SSA to calculate the benefits and expenses of the Social Security program.
An actuarial life table typically consists of several columns, such as:
- Exact age: The age at the beginning of the interval.
- Death probability: The probability that a person of a given age will die within one year.
- Number of lives: The number of survivors at the beginning of the interval out of a hypothetical cohort of 100,000 individuals born at the same time.
- Life expectancy: The average number of years remaining for a person of a given age.
Here is an example of an actuarial life table for the US population in 2019, as used in the 2022 Trustees Report by the SSA:
 |
| Image: Moneybestpal.com |
