Changes of Unequal Structure of Stratification in Modern Japan

通过对日本社会的社会流动性中机会不平等的时间变化进行分析，区分了时间效应、世代效应和年龄效应，得出了以下结果。通过Logistic回归模型和对数线性模型对机会不平等（阶级继承倾向）的分析，这三点得到了明确。第一，随着年龄的增长，机会不平等现象减少的趋势十分明显。第二，由于周期效应和群体效应的复合变化，一个社会作为一个整体所具有的不平等机会的总和已经减少和均等。第三，代际流动对代际流动中的机会不平等有一定的均等化作用，尤其是在个体户阶层中，进入阶层的流动机会不平等和进入当前阶层的流动机会不平等发生了不同的时间变化，其影响因素也不同。在进入阶级的流动中，农民继承权的迅速减少使机会不平等的总和趋于均衡，而人们的阶级分配也从父辈阶级继承权的继承明显转变为受教育程度的选择。与进入社会阶层的机会不平等程度相比，进入社会阶层的机会不平等程度因年龄效应而降低。这意味着代际流动与代内流动相等。从分析结果来看，日本社会的社会流动机会不平等，从农民减少、分配原则通过学历向入门阶层的渗透、代内流动的均等化效果等方面来看，到90年代为止呈现出均等化的变化。

The following findings were obtained as a result of the analyses to detect temporal changes of unequal opportunity in social mobility of Japanese society, distinguishing time, cohort, and age effects. The three points became clear by the analyses of logistic regression model and log linear model to estimate unequal opportunity (tendency of class inheritance). First, the tendency that unequal opportunity decreases as age increases was salient. Second, the sum of unequal opportunity which a society has as a whole has been reduced and equalized as a result of compounding changes by period effect and cohort effect. Third, intra-generational mobility has an effect to equalize unequal opportunity in inter-generational mobility, in several classes, especially self-employed classes.After all, unequal opportunities in mobility to entry class and in mobility to current class have carried out different temporal changes and have different factors to change, each other. In mobility to entry class, the sum of unequal opportunity was equalized by rapid decrease of farmer's inheritance according to cohort transition, and the distribution of people to classes was remarkably changed into one selected by educational credential from inheritance of father's class. The level of unequal opportunity in mobility to current class was reduced by age effect in comparison with that of mobility to entry class. This means that inter-generational mobility was equalized by intra-generational mobility. As for the result of analyses, unequal opportunity in social mobility of Japanese society showed changes equalized till the 1990s according to reduction of farmers, penetration of the distribution principle to entry class by educational credential, and the equalization effect by intra-generational mobility.