This paper draws on a unique data set, hojok (household registers), to estimate numeracy levels in Korea, 1550–1630, and evidence on Japan and China from the early modern period until 1800. We found that a substantial share of East Asians rounded their ages to multiples of five. However, the...

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,...