Studies of childhood development have suggested human capital is accumulated in complex and nonlinear ways. Nonetheless, empirical analyses of this process often impose a linear functional form. This paper investigates which technology assumptions matter in quantitative models of human capital production. I propose a general‐to‐restricted procedure to test the production technology, placing constraints on a modified McCarthy function, from which transcendental, constant elasticity of substitution, log‐linear and linear models are obtained as special cases. Applying the procedure to data on child height from the Young Lives surveys, as well as cognitive skills, I find that the technology of human capital production is neither log‐linear nor linear‐in‐parameters; rather, past and present inputs act as complements. I recommend that maintained hypotheses underlying functional form choices should be tested on a routine basis.

中文翻译：

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测试人力资本生产技术：从一般到限制的框架

对儿童发展的研究表明，人力资本是以复杂和非线性的方式积累的。尽管如此，对这个过程的经验分析常常强加一种线性函数形式。本文研究了哪些技术假设在人力资本生产的定量模型中很重要。我提出了一个从通用到受限的程序来测试生产技术，对修改后的麦卡锡函数施加约束，从中获得超越的、恒定的替代弹性、对数线性和线性模型作为特殊情况。将该程序应用于来自 Young Lives 调查的儿童身高数据以及认知技能，我发现人力资本生产技术既不是对数线性也不是线性参数；相反，过去和现在的投入是互补的。