Essays on Human Capital

This thesis comprises three essays that examine how human capital shapes economic outcomes across three distinct dimensions: as a motive for individual choices, as a determinant of industry composition, and as a measure of allocative efficiency. Each essay combines novel empirical evidence with quantitative macroeconomic models to study a specific channel through which the accumulation, availability, or distribution of human capital influences economic activity. Chapter 1, "Worker Heterogeneity and Optimal Unemployment Insurance", studies how endogenous human capital accumulation interacts with the design of unemployment insurance (UI). Using an OLG model with learning-by-doing, depreciation during unemployment, and worker heterogeneity in age and ability, calibrated to US data, I show that fully conditional age- and ability-dependent benefits generate welfare gains of 0.35% of consumption. A simple non-conditional policy combining a replacement rate with a benefit floor and cap captures roughly 60% of these gains (about 0.2% of consumption). The non-linearity introduced by floor and cap mimics the targeting of conditional policies because income correlates strongly with age and ability, allowing policymakers to align UI with workers' own incentives to invest in experience without conditioning benefits on individual characteristics. Chapter 2, "Demographic Change and Technological Choice", analyzes how demographic shifts alter the relative availability of human capital and thereby reshape firms' technology choices across sectors. Applying the German Federal Employment Agency's labor scarcity methodology over an extended horizon, I document a structural break around 2010 after which labor scarcity rises sharply in both production and services, accompanied by a pronounced increase in software and R&D investment in production sectors but largely flat investment in services. I develop a multi-sector model that combines demography-induced capital abundance with directed technological change, in which the substitutability between machines and human capital determines whether a sector becomes high-tech or low-tech. The model replicates the observed investment patterns and shows that secular structural change and technological polarization are, in part, the consequence of a fundamental change in the availability of human capital. Chapter 3, "Labor Market Mismatch", examines how the alignment of idle human capital and vacant positions across geography and occupation affects labor market efficiency. Building on historical reports of the German Federal Employment Agency and the Sample of Integrated Labour Market Biographies (SIAB), I construct a novel dataset on vacancies and searching workers in Germany spanning nearly four decades. Extending the framework of Şahin, Song, Topa, and Violante (2014), I derive an explicit planner solution and develop measures of mismatch that account for sectoral heterogeneity in matching efficiency, job loss rates, and labor productivity. The results indicate economically meaningful mismatch in the German labor market, but also suggest that the distributional costs of policies aimed at reducing it are likely to far exceed their efficiency gains. Taken together, the three essays underscore that there is no single, universally applicable concept of human capital: each perspective requires its own measurement and modeling strategy. At the same time, the underlying mechanisms are deeply interconnected, as individual accumulation decisions, sectoral demand for skills, and the spatial and occupational distribution of workers jointly shape aggregate outcomes. The thesis advances both methodology and data for the analysis of human capital and points to several promising avenues for future research.