Projection of Social Burden of the Elderly in Japan Using INAHSIM-II

By using a microsimulation model named INAHSIM, we conducted a household projection in Japan for the period of 2011–2060. Due to rapid aging of the population, the distribution of the elderly (65 years old or older) by living arrangement and dependency level has a profound impact on the future social burden. In this paper, we measured the social burden of the elderly by three variables: (1) institutionalization rate (percentage of the elderly living in institutions), (2) parent-child ratio (relative number of old parents taking into account the number of brothers and sisters), and (3) one-year transition matrix of the elderly by household type. Especially, the choice of the elderly among (a) living independently, (b) coresident with child households, and (c) moving to institutions are crucial indicators for the future social burden of the elderly in Japan. 1. Introduction The household is one of the most important statistical bases for policy formulation on health and welfare. The average number of household members is declining, and the number of single households is increasing in Japan. However, the household is still an important unit for various policies, and elderly in one-person household tend to require support of various kinds in aging society. Although expanding recently, statistical information on households and families is still inadequate, to understand the dynamic process of formation and dissolution of households and families in a systematic and coordinated way. Dynamic microsimulation models are considered to be the most suitable method to observe the dynamic evolution of households and families and to forecast their future trends. While most microsimulation models developed to date have focused on the household sector, a number have been created which simulate the behavior of businesses, rather than individuals or households [1]. However, the dynamic microsimulation method does have some drawback, including difficulties in obtaining the initial population as well as estimating the transition probabilities. INAHSIM-II is a solution to avoid the difficulty to obtain initial population for the model. INAHSIM (Integrated Analytical Model for Household Simulation) is a dynamic microsimulation model, which was first developed in 1984-85 in Japan by using an actual initial population derived from a national household survey. The main purpose of INAHSIM was to prepare projections to get information on the future number and composition of households, and to analyze households and families in terms of the dynamic transition of household types,