A STUDY ON THE LIFE OF THE JAPANESE HOUSING STOCK ESTIMATED FROM THE HOUSE AND LAND STATISTICS SURVEY

Abstract

This paper first proves that the life of the Japanese housing stock can be calculated depending solely on the housing stock data published in the House and Land Statistics Survey (the Ministry of Internal Affairs and Communications) which has been regarded inappropriate for that purpose mainly because of its inconsistency with the flow data shown in the House Building Statistics (the Ministry of Land, Infrastructure, Transport and Tourism). Having Applied the Kaplan-Meier's method, the life is given by the 50 percentile value of the accumulated survival ratio of the same cohort. The system dynamics model thus reconstructed from the House and Land Statistics Survey consequently shows a good accordance with the House Building Statistics. The change of the life since 1973 indicates that the life has been consistently becoming longer over the surveyed period, that houses built more recently have longer life, that rebuilding (houses rebuilt on the same lots) has been gradually increasing and so on. The increasing vacancy ratio (surplus stock), on the other hand, suggests the importance of further investigation into the regional difference in the housing needs particularly when the 200 year long life house project has been launched by the government and at the same time when regional disparities of wealth has become problematic.