Economic Theories of Poverty Measurement: The Current and Future Issues

本稿の目的は，貧困を把握する指標やその背後にある経済理論を大まかに展望するとともに，今後の研究課題を検討することである．そのためにまず，相対貧困と絶対貧困を比較し，貧困をどう定義するかという問題を考える．第2に，様々な貧困指標の特徴と貧困に関する公理との関係，そしてその政策的含意を整理する．第3に，日本のデータに基づき，貧困変化を要因分解するとともに，そこから示唆される政策の方向性を検討する．第4に，時間の貧困や支出関数に基づく貧困指標，多次元の貧困分析など，貧困に関する新たなアプローチを紹介する．近年の貧困研究では，経済学・社会学など社会科学を専門とする研究者だけでなく，医学，疫学，心理学など様々な学問分野の研究者との間での共同研究が積極的に進められている．今後も，貧困の決定要因や貧困の諸効果の多面的な理解を進める上で，多様な学問分野の融合による発展的研究が進むことが期待される．This paper aims to broadly overview poverty indexes, to investigate their underlying economic theories, and to consider important future study points. We firstly compare the concepts of absolute poverty and relative poverty, and discuss how we should define poverty. Secondly, we summarize the axioms which the representative poverty indexes satisfy and their outstanding characteristics. Thirdly, we examine the main factors of the change in poverty level during the 2000s in Japan, using decomposition methods, and draw policy implications. Fourthly, we introduce the outline of new frontiers for poverty measurement such as the consumption dominance curve and multi-dimensional poverty indicies including the Alkire and Foster method and time poverty. In recent years, much poverty research which crosses into various types of collaborative academic fields such as medicine, epidemiology, and psychology as well as the social sciences have been actively conducted. It can be expected that constructive researches associated with amalgamation of a variety of academic fields will make progress in the future