Beyond high-income countries: Low numeracy is associated with older adult age around the world

Background. Numeracy, or the ability to understand and use numbers, has been associated with obtaining better health and financial outcomes. Studies in high-income countries suggest that low numeracy is associated with older age—perhaps especially among individuals with lower education. Here, we examined whether findings generalize to the rest of the world. Methods. Gallup surveyed .150,000 participants for the 2019 Lloyd’s Register Foundation World Risk Poll, from 21 low-income, 34 lower-middle income, 42 upper-middle income, and 43 high-income countries. Low numeracy was operationalized as failing to correctly answer, ‘‘Is 10% bigger than 1 out of 10, smaller than 1 out of 10, or the same as 1 out of 10?’’ Results. Regressions controlling for participants’ education, income, and other characteristics found that, worldwide, low numeracy was associated with older age, lower education, and their interaction. Findings held in each country-income category, although low numeracy was more common in low income countries than in high-income countries. Limitations. Age differences may reflect cohort effects and life span–developmental changes. Discussion. Low numeracy is more common among people who are older and less educated. We discuss the need for education and interventions outside of the classroom.