Life expectancy has increased considerably worldwide over the past few decades. It is well known that life expectancy is an important measure of the mortality rate, and that an increase in life expectancy is the result of a decrease in the mortality rate. In Korea, the mortality rate improved rapidly in a short period compared to advanced countries, and the life expectancy in Korea has been improved by about 20 years for 48 years, from 58.7 years old for men and 65.8 years old for women in 1970 to 79.7 years old for men and 85.7 years old for women in 2017.
The relative contribution of the mortality rate to the change in life expectancy is not necessarily the same across all age groups. Therefore, this study is to more closely measure and explain the effect of the change in the mortality rate on life expectancy by calculating the age-specific contribution to the improvement of the mortality rate and the change in life expectancy or the difference in life expectancy by gender. To this end, we used Arriaga (1984)‘s decomposition, which measures the change in life expectancy in consideration of the change in the age-specific mortality rate, which applied the principles of a life table, and analyzed the contribution of the change in the age-specific mortality rate to the improvement of the mortality rate and the change in life expectancy of Korea from 1970 to 2017, and visually expressed it using the R package ROMI.plot The results of the analysis showed that Korea is showing an improvement in the mortality rate in all age groups, and the mortality rate especially for those in their 60s and 80s is improving rapidly, but all of the age groups did not show the same mortality rate improvement. Contribution by age according to the increase in life expectancy of those in their 60s and 80s was higher than that of other age groups, indicating that the elderly population of both men and women mainly contributed to the improvement of Korean life expectancy during the observation period. And it was found that all age groups positively contributed to the gender gap in life expectancy at birth.
Key words: Life expectancy, age-specific mortality rate, improvement rate of mortality, age-specific contribution