Principle of measuring longevity using the calculative method of life expectancy and health-adjusted life expectancy

Abstract

Life expectancy and health-adjusted life expectancy are population longevity indexes covering mortality, illness, and disability. This article aims to explain the concepts and methods of measuring the longevity of both indexes, as well as their benefits and implementation. Life expectancy is the average age that the population is expected to live, which is calculated from the life table that consists of various functions that are related to each other. The result of the life table is life expectancy. Health-adjusted life expectancy is the average age of the population expected to be healthy or in good health. It is a measurement of the health status of the population developed by the World Health Organization. It covers both death and illness, a measure that adjusts the life expectancy calculated by using the life table, which is adjusted to life expectancy at various levels of health in each stage of life.  Both indicators are useful in many aspects, such as health policy application, disease control, medical treatment, and improving the quality of life. For example, it is useful for measuring the change in the health status of a population, evaluating the effectiveness and efficiency of disease control and prevention, for prioritizing the strategies in health policy planning and health care services.