Life table

a representation of the probable years of survivorship of a defined population of subjects

Description
Since survivorship is changed by new methods of prevention or treatment, a diachronic study is commonly used, because the main interest lies in the composite structure of the current population. In the summarizing technique used to describe the pattern of mortality and survival in a population, survivors to age x are denoted by the symbol lx and the expectation of life at age x is denoted by the symbol x.