Life tables, sometimes called “life tables” rather than “death tables,” represent people’s lives as they pass away and reflect demographers’ interest in mortality and cohort attrition. Ketfitz defined the life table as a method for quantifying mortality in terms of probability in 1960. He says it is worth examining a population model that covers the simplest case: a cohort or group of persons born at the same time just before migration and followed through successive ages until they pass away.
A life table comprises numerous columns that, starting at birth, display the values of several life-table functions at each age. The mortality rates at each age and the likelihood of dying between years are shown in the first column. Different columns display other features, such as the number of individuals present at each age, if deaths happened per the life table, or if fertility equals mortality. It also includes a column for life expectancy, which displays the typical number of years people have remaining to live. Another key column is the number of individuals that survived and emerged from the original cohort.
The period life table and the cohort life table are the two primary forms of life tables that are often used.
Period Life Table #
The static life table, commonly referred to as a period life table, shows the death rates for a certain population for a particular period. As a result, it displays the present likelihood of death. The period life table is based on annual death rates. The mortality rates are calculated by comparing estimates of the population’s size at certain ages against counts of people who died at those ages. The periodic life table considers the death rates experienced by various demographic ages during a specific period. The life table denotes the current life table unless otherwise indicated.
Cohort Life Table #
The cohort life table, which tracks a recorded birth cohort until all its members pass away, is the most basic. This life table is created by comparing the number of people who live on a specific birthday to the number of deaths that occur in the year or years that follow.
The cohort life table is widely used more frequently because it can predict future changes in mortality rates for a certain group. The cohort life table is also recommended because it enables the analysis of changes in mortality rates across time.
A life table represents mortality in years by showing what would happen to a hypothetical cohort if the current age-specific death rate at each age stayed constant. Life expectancies are calculated by taking the simple average of age-specific mortality rates. At the same time, risks are calculated using the periodic life table’s current mortality rates for each age.
Cohort Effects The life table and total fertility rates are based on the experience of a cohort that goes through the same experience across time, supposing that age-specific rates remain constant over time. Furthermore, because age, time, and cohorts are related, it is extremely challenging to determine whether a correlation with one of these features causes another change.
Since death rates are utilized as inputs for population prediction, the standard life table has many uses. There are various variations of the conventional life table, such as the segregated life table by gender, because males often have greater death rates than women.
Mortality does not significantly influence the social structure, despite the importance of population age distribution in this. According to one definition, the percentage of the population over 65 impacts fertility rates, which determine the number of children born per woman of reproductive age.
