Time of Day and High Stakes Cognitive Assessments

A variety of external conditions may affect individual performances in high stakes cognitive assessments, with potentially lasting consequences on earnings and career. We provide the first causal evidence that the time of the day is an important condition affecting the performance at the moment of an evaluation. Exploiting a setting in which cognitive assessments are quasi-randomly assigned at a different time of day, we find that peak performance occurs in the early afternoon. The estimated time of day effects follow specific patterns consistent with the circadian rhythm, which suggests that biological factors are important determinants of performances even in economically meaningful settings.