Does chronotype affect academic performance? Using data from Add Health, which uniquely combines official high school transcripts with DNA-based information, this paper examines whether the genetic predisposition for a morning-oriented chronotype affects high school GPA. Exploiting the natural experiment of random genetic inheritance among full siblings, I estimate causal effects. Results indicate that, holding the genetic predisposition for educational attainment fixed, a higher propensity for morningness has a positive and statistically significant impact on high school GPA. This effect is driven by the early birds, who benefit from a closer alignment between their biological and the social clocks.
We estimate the effect of sleep on labor productivity addressing the two main challenges in time use research: the unavoidable substitutions among activities implied by the time budget constraint and the endogeneity of the allocation of time. We use complete time diary data to identify the relative effect of sleep vs. non-work activities among employees working the same number of hours, and account for the endogeneity of time use choices by leveraging longitudinal information on productivity in a value-added specification. We show that, when work hours are held constant, substituting sleep with other non-work activities does not affect labor productivity.
This work examines, for the first time, whether innate circadian preferences, known as chronotype, drive self-selection into alternative work shifts and occupations; and it evaluates how the alignment of biological and social clocks impacts early labour market outcomes. Leveraging a representative sample of US early adults from Add Health and a polygenic index (PGI) for morningness to characterise chronotype, I find no evidence of chronotype-based sorting. Then, I assess the implications of the lack of matching between workers’ circadian and work timings. I find a positive relationship of morningness with job satisfaction, while not with earnings. This relationship plausibly stems from higher likelihood of early chronotypes to find roles aligned with their innate circadian rhythms, which improves the synchrony between biological and social clocks and ultimately enhances overall job satisfaction.
In progress