Does schooling improve cognitive abilities at older ages? Causal evidence from nonparametric bounds

We revisit much-investigated relationships between schooling and health, focusing on schooling impacts on cognitive abilities at older ages using the Harmonized Cognition Assessment Protocol in the Health & Retirement Study (HRS) and a bounding approach that requires relatively weak assumptions. Our estimated upper bounds on the population average effects indicate potentially large causal effects of increasing schooling from primary to secondary; yet, these upper bounds are smaller than many estimates from the literature on causal schooling impacts on cognition using compulsory-schooling laws. We also cannot rule out small and null effects at this margin. We do, however, find evidence for positive causal effects on cognition of increasing schooling from secondary to tertiary. We replicate findings from the HRS using older adults from the Midlife in United States Development Study Cognitive Project. We further explore possible mechanisms through which schooling may be working-such as health, SES, occupation and spousal schooling-finding suggestive evidence of effects through such mechanisms.