livstabeller

Livstabeller, or life tables in English, are statistical tables that summarize the mortality experience of a population. They provide measures such as the probability of dying within an age interval, the number of people alive at the start of each interval, and the expected remaining life at a given age. The term livstabeller is used in Danish, Norwegian, and Swedish to denote these tables, which can be constructed for the whole population or for subgroups defined by sex, region, or socioeconomic status.

A typical life table lists age x, the number alive at the start of the interval (l_x), the number dying during the interval (d_x), the mortality rate or probability of dying (q_x), and the probability of surviving (p_x). Derived quantities include L_x (person-years lived in the interval), T_x (total person-years remaining beyond age x), and e_x (life expectancy at age x). Life tables may be abridged (grouped into age bands) or complete (single-year ages). There are two main forms: period life tables, reflecting mortality rates during a defined period, and cohort life tables, following a birth cohort over time to track its mortality experience.

Uses and history: life tables are fundamental in actuarial science for pricing life insurance and annuities, calculating pension liabilities, and setting reserves. They also support demographic research and public health planning by measuring life expectancy and mortality risk. The concept traces to early modern observations of mortality, with notable developments by Halley and Graunt, and has evolved with improvements in vital statistics, data quality, and analytical methods.