Alderson, Arthur S., Jason Beckfield, and François Nielsen, "Exactly How Has Income Inequality Changed?: Patterns of Distributional Change in Core Societies", (2005)

Alderson, Arthur S., Jason Beckfield, and François Nielsen, 2005, "Exactly How Has Income Inequality Changed?: Patterns of Distributional Change in Core Societies", International Journal of Comparative Sociology December, 46: 405-423.

the Luxemburg Income Study（LIS）の16カ国のデータを使って、1960年後半から2000年代はじめまでの世帯所得の不平等の変化を分析。
用いている方法は、相対的分布法（relative distribution methods）。

The recent resurgence of income inequality in some of the core societies has spawned a wide-ranging debate as to the culprits. Progress in this debate has been complicated by the fact that many of the theories that have been developed to account for the inequality upswing imply radically different patterns of distributional change, while predicting the same outcome in terms of the behavior of standard summary measures (e.g. a rise in the Gini coefficient or in Theil’s inequality). Handcock and Morris (1999) have developed methods that allow the analyst to precisely identify patterns of distributional change and a set of summary measures to characterize such changes. These are based on the relative distribution, defined for our purposes as the ratio of the fraction of households in the baseline year to the fraction of households in the comparison year in each decile of the distribution of income. We use the available high-quality data from the Luxemburg Income Study to explore the evolution of household income inequality in 16 core societies. We describe exactly how inequality grew in some core societies since the late 1960s and discuss the extent to which patterns of distributional change were homogeneous or heterogeneous across the core. We find that: 1) rising inequality is generally associated with polarization, rather than upgrading or downgrading alone; 2) among those societies experiencing the largest increases in inequality, upgrading typically takes precedence over downgrading in the course of such polarization; and 3) declining inequality, where it occurs, has been the result of convergence, with the magnitude of the shift from the lower tail to the middle exceeding that of the shift from upper tail to the middle.

シンプルな分析、シンプルな論文。

分析結果によると、
（1）16カ国のうち、11カ国が不平等の拡大を経験（イギリスにおける不平等拡大が最も大きかった）。そして不平等の拡大は、一般的に、upgrading（分布の上位へのシフト）やdowngrading（分布の下位へのシフト）だけではなく、polarization（二極化）と結びついていた
（2）不平等の大きな拡大を経験した社会では、二極化の過程で、upgradingがdowngradingよりも大きかった。
（3）いくつかの国（カナダやスウェーデン）は、不平等の減少を経験した。そしてそれは、convergence（分布の中位への収斂）の結果である。

ジニ係数などの、the summary indexesでは、分布の変化を見極めることができない。
相対分布法とは、Mark S. HandcockとMartina Morrisによる1999年のRelative Distibution Methods in the Social Sciencesという本で提案されたもの。これをきちんと読んで、私も日本のデータで同じような分析をしてみようと思う。