Quantifying Quantitative Literacy: Age Heaping and the History of Human Capital
利用年龄数据在整数年龄上的堆积现象（年龄堆积）来测量定量推理能力（数理能力），构建了覆盖广泛时空范围的数据库，发现识字率与数理能力高度相关，并揭示西欧早在1600年就已达到高数理水平，远早于大众教育和工业化。
Age data frequently display excess frequencies at attractive numbers, such as multiples of five. We use this “age heaping” to measure cognitive ability in quantitative reasoning, or “numeracy.” We construct a database of age heaping estimates with exceptional geographic and temporal coverage, and demonstrate a robust correlation of literacy and numeracy, where both can be observed. Extending the temporal and geographic range of our knowledge of human capital, we show that Western Europe had already diverged from the east and reached high numeracy levels by 1600, long before the rise of mass schooling or the onset of industrialization.