Social Stratification Theory and Population Aging Reconsidered

Japan has the world’s most aged population. To examine this aging population from a theoretical perspective of social stratification, we focused on household structure, income structure, and economic well-being, including both disposable income and savings. Two main topics are discussed in this paper: first, the relationship between the aging population and income inequality, focusing on changes in household structure and income structure; and second, the level of economic well-being in old age (when the relationship to the labor market becomes blurred) considering individuals’ previous work life. I analyzed two survey datasets: the Comprehensive Survey of People’s Living Conditions, conducted by the Ministry of Health, Labor and Welfare since the mid-1980s, and the 2015 National Survey of Social Stratification and Social Mobility. These analyses confirmed that the change in household structure (more elderly heads of household) explains the growth of income inequality since the mid-1980s. While income inequality among households with working-age heads increased, its impact was limited to an overall increase in income inequality due to declining household size. On the other hand, income inequality among households with older heads was largely explained by market income, and this scenario has not changed for the past 30 years. The level of economic well-being among older adults was determined by age, marital status, educational credentials, and work situation at age 50 for both genders.