Age data frequently display excess frequencies at round or attractive ages, such as even numbers and multiples of five. This phenomenon of age heaping has been viewed as a problem in previous research, especially in demography and epidemiology. We see it as an opportunity and propose its use as...

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,...