Middle-aged and elderly people were having an important effect on life expectancy growth. Over the last several decades, life expectancy has been rising substantially throughout the world. It is well known that life expectancy is an important measure of mortality and that the increase in life expectancy is the result of a decline in mortality. However, the relative contributions of mortality rates to the change in life expectancy are not necessarily the same across all age groups. Therefore, this study aims to measure and explain the effects of changes in mortality on life expectancy by calculating age-specific contributions to life expectancy changes. For this purpose, Arriaga (1984) 's life expectancy decomposition method was used to measure the change in life expectancy, taking into account the change in age-specific mortality. We analyzed the contribution of age-specific mortality changes to changes in Korean male and female life expectancy from 1970 to 2018. In addition, to better understand the characteristics of dynamic mortality, we calculated and visually represented mortality improvement rates. This makes it possible to intuitively derive information from age-specific mortality changes. This paper demonstrates an association between an improvement in life expectancy and a change in age-specific mortality by evaluating the contribution of age-specific mortality changes to elucidate the growth mechanism of life expectancy in Korea. The results of the analysis showed that before the 1990s, when the death level was high, the improvement of infant and young children mortality played an important role in increasing expectancy. However, as death levels improved, it was concluded that improvements in death levels for middle-aged and elderly people were having an important effect on life expectancy growth.

Key words: Age-specific mortality rate, Improvemenast rate of mortality, Life Expectancy, Decomposition