BackgroundBy providing high-quality, internationally comparable data on the cognitive skills of working-age adults, the Programme for the International Assessment of Adult Competencies (PIAAC) offers great potential for illuminating the complex interplay of formal qualifications and skills in shaping labor market attainment as well as social inequalities more broadly. I argue that PIAAC can be used to construct direct, country-level measures of the ‘skill transparency’ or ‘signaling value’ of formal qualifications, that is, of how informative the latter are about a person's actual skills. The primary goal of the analysis is to extend previous work on skills gaps by educational attainment and map cross-national variation in the internal skills homogeneity of educational groups as a second dimension shaping the signaling value of educational degrees. I also explore whether the internal homogeneity of educational groups is related to national (secondary) education systems.MethodsI use a sample of 30,646 20-to-34-year-olds in 21 countries that participated in the first round of PIAAC. The internal homogeneity of educational groups is measured using the residual standard deviation of literacy and numeracy skills after adjusting for sex, age, and foreign-birth/foreign-language status. Residual standard deviations for the different educational groups are subjected to a factor analysis to construct a one-dimensional measure of internal homogeneity for each country. This index of internal homogeneity is then related to education system characteristics in a series of country-level regressions.ResultsThe internal homogeneity of educational groups with respect to literacy and numeracy skills varies considerably across countries and is highly correlated across both skill domains and educational groups. Educational groups tend to be more homogeneous in countries with stronger (ability-related) tracking in secondary education. In addition, there is some evidence that internal homogeneity declines when instructional resources such as computer hardware and lab equipment are distributed more unequally across schools. An unexpected finding is that internal homogeneity is negatively associated with standardization of input (e.g., curricula, textbooks).ConclusionsThe signaling value of educational degrees varies substantially across advanced economies, not only in terms of skills gaps among educational groups, but also in terms of their internal homogeneity. Some features of secondary education systems appear to be systematically related to the extent of internal homogeneity. The findings lend empirical support to so far untested assumptions about the relationship between formal qualifications and skills in cross-national research on labor market inequalities.

中文翻译：

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衡量教育程度的信号价值：中等教育系统和教育群体的内部同质性

背景通过提供有关工作年龄成年人认知技能的高质量，国际可比的数据，国际成人能力评估计划（PIAAC）在阐明正式资格和技能在塑造劳动力市场成就方面的复杂相互作用方面具有巨大潜力。以及更广泛的社会不平等。我认为，PIAAC可用于构建国家/地区级水平的对正式资格的“技能透明度”或“信号价值”的衡量方法，即，后者对于个人实际技能的信息丰富程度。该分析的主要目标是通过教育程度来扩展以前在技能差距方面的工作，并绘制教育群体内部技能同质性的跨国差异，作为塑造教育程度信号价值的第二个维度。我还探讨了教育群体的内部同质性是否与国家（中学）教育体系有关。方法我使用了参与PIAAC第一轮调查的21个国家的30646名20至34岁的样本。在调整了性别，年龄和外来出生/外语状态后，使用识字和计算能力的剩余标准差来衡量教育群体的内部同质性。对不同教育群体的残差标准差进行因子分析，以构建每个国家内部同质性的一维度量。然后，在一系列国家层面的回归中，这种内部同质性指标与教育系统特征相关。结果教育群体在识字和计算能力方面的内部同质性在不同国家之间存在很大差异，并且在技能领域和教育群体之间高度相关。在中学教育（与能力相关）具有更强追踪能力的国家中，教育群体趋向于同质化。另外，有证据表明，当计算机硬件和实验室设备等教学资源在学校之间分配不均时，内部同质性会下降。一个出乎意料的发现是内部同质性与投入的标准化（例如课程，教科书）负相关。结论教育程度的信号价值在发达经济体之间差异很大，不仅在教育群体之间的技能差距方面，而且在它们的内部同质性。中等教育系统的某些特征似乎与内部同质性的程度系统地相关。这些发现为迄今为止关于劳动力市场不平等的跨国研究中正式资格与技能之间关系的未经检验的假设提供了实证支持。结论教育程度的信号价值在各个发达经济体之间差异很大，不仅在教育群体之间的技能差距方面，而且在其内部同质性方面。中等教育系统的某些特征似乎与内部同质性的程度系统地相关。这些发现为迄今为止关于劳动力市场不平等的跨国研究中正式资格与技能之间关系的未经检验的假设提供了实证支持。结论教育程度的信号价值在各个发达经济体之间差异很大，不仅在教育群体之间的技能差距方面，而且在其内部同质性方面。中等教育系统的某些特征似乎与内部同质性的程度系统地相关。这些发现为迄今为止关于劳动力市场不平等的跨国研究中正式资格与技能之间关系的未经检验的假设提供了实证支持。