In this study, we investigate the relationship between social origin and educational attainment in Spain from 1946 to 1989, testing the theory of persistent inequalities and using two different methodological approaches: the margin-free versus the margin-dependent traditions. More specifically, we will compare the results of the traditional log-linear measures used most frequently in this field with those of the mutual information index, a measure that considers the marginal change in both educational expansion and occupational upgrading. Moreover, we apply the decomposition of this index, as proposed by Jann & Seiler, which allows us to simultaneously observe and distinguish between the internal component (margin-free: not accounting for changes in marginal distributions such as odds ratios) and the marginal component (non-margin free: including and measuring marginal effect). Previous research using margin-free models reveals educational inequalities in Spain to be constant, whereas our results show a marked decline in educational inequalities when the weights obtained by the marginal distribution are taken into account. We argue that this decomposition may enrich our view of educational inequalities without disregarding traditional margin-free measures.

在这项研究中，我们调查了 1946 年至 1989 年间西班牙的社会出身与教育程度之间的关系，检验了持续不平等理论并使用了两种不同的方法论：无边际传统与边际依赖传统。更具体地说，我们将比较该领域最常用的传统对数线性度量的结果与互信息指数的结果，互信息指数是考虑教育扩张和职业升级的边际变化的度量。此外，我们应用 Jann 和 Seiler 提出的该指数的分解，这使我们能够同时观察和区分内部成分（无保证金：不考虑边际分布的变化，例如优势比）和边际成分（非免保证金：包括和衡量边际效应）。先前使用无边际模型的研究表明，西班牙的教育不平等是恒定的，而我们的结果表明，当考虑边际分布获得的权重时，教育不平等显着下降。我们认为，这种分解可能会丰富我们对教育不平等的看法，而无需忽视传统的无边际措施。