”Physicists’ approach to studying socio-economicinequalities: Can humans be modelled as atoms?”
Kiran Sharma and Anirban Chakraborti https://arxiv.org/abs/1606.06051
A brief overview of the models and data analyses of income, wealth, consumption distributions by the physicists, are presented here(物理学者による所得分布等のモデルとデータ分析の簡単な概観が述べられている). It has been found empirically that the distributions of income and wealth possess fairly robust features, like the bulk of(〜の大部分) both the income and wealth distributions seem to reasonably fit both the log-normal and Gamma distributions, while the tail of the distribution fits well to a power law (as first observed by sociologist Pareto)(実証的に，所得と富の保有の分布はかなりロバストで，所得と富の分布の大宗bulkはかなり対数正規とガンマ分布に似ている一方で分布の尾tailの分布は(社会学者パレートに先ず観測された様に)冪法則に良くfitしている). We also present our recent studies of the unit-level expenditure on consumption(単位水準消費支出？) across multiple countries and multiple years, where it was found that there exist invariant(不変量・不変の) features of consumption distribution(消費分布に不変量の特徴→消費分布が一定である特徴？): the bulk is log-normally distributed, followed by a power law tail at the limit. The mechanisms leading to such inequalities and invariant features for the distributions of socio-economic variables are not well-understood. We also present some simple models from physics and demonstrate how they can be used to explain some of these findings and their consequences.
B.K. Chakrabarti, A. Chakraborti, S.R. Chakravarty and A. Chatterjee, Econophysics ofIncome and Wealth Distributions (Cambridge University Press, Cambridge, 2013).
S. Sinha, A. Chatterjee, A. Chakraborti and B.K. Chakrabarti, Econophysics: An Introduc-tion (Wiley-VCH, Berlin, 2010).
F. Slanina Essentials of econophysics modelling (Oxford University Press, Oxford, 2013).
M. Patriarca, E. Heinsalu, A. Singh and A. Chakraborti, “Kinetic Exchange Models asDDimensional Systems: A Comparison of Different Approaches”, in Eds. F. Abergel et al.,Econophysics and Sociophysics: Recent Progress and Future Directions(Springer, Milan,2017), pp 147-158.
所得分布の研究は古くからある研究であり，所得分布は，社会保障，労働，財政，マクロ，消費，経済統計など多くの領域にまたがる問題である．橘木俊詔（1998）『日本の経済格差』および，大竹文雄（2005）『日本の不平等』が，日本の経済格差の問題について大きな論争を呼びおこした．その結果，日本の不平等度が米国より高いということはないが，90年代以降，少しずつ上昇していることにはコンセンサスができてきている．一方，Journal of EconomicInequalityが2003年に発刊されるなど，世界的にも所得格差の問題は関心を集めている．
所得分布で用いられる…々の分布についてはKleiber and Kotz (2003)に詳しい説明がある．そして，本研究では２パラメータのパレート分布および対数正規分布を用いる．…指数分布の部分順序統計量にもとづく推定の研究はSaleh and Ali(1966)など，1960年代に盛んに行われていたが，Saleh and Ali (1966)では，この推定量をABLUE(Asymptotically BLUE)としている．
Nirei, M. and W. Souma (2007). “A Two Factor Model of Income Distribution Dy-namics,”Review of Income and Wealth,53, 440?459.
Saleh, A. K. Md. E. and M. M. Ali (1966).“Asymptotic Optimum Quantiles for theEstimation of the Parameters of the Negative Exponential Distribution,”Annals ofMathematical Statisitcs,37, 143?151.
Singh, S. K. and G. S. Maddala (1976). “A Function for Size Distribution of Incomes,”Econometrica,44, 963?970.
Kleiber, C and S. Kotz (2003).Statistical Size Distributions in Economics and Actu-arialSciences, Wiley, New York
