You sneeze, you lose: The impact of pollen exposure on cognitive performance during high-stakes high school exams

Pollen is known to cause allergic reactions in approximately 20% of the population. These reactions have significant detrimental effects on sleep, concentration, and cognitive performance. Coincidentally, in many countries the local proliferation of pollen is concentrated in the spring when students take high-stakes exams. Despite these observations, the effect of pollen allergies on school performance has so far received nearly no attention from economists. Using administrative data on Norwegian high school students merged with daily pollen counts, this paper examines the effect of exposure to pollen spores on exam outcomes. I take advantage of the fact that students take several exams in a variety of subjects on different dates, but at the same location, to implement a student fixed effects model. In all specifications increased pollen proliferation on the exam date is found to significantly reduce cognitive performance measured by examination grade. On average, a one standard deviation increase in the ambient pollen level at the mean leads to a 2.5% of a standard deviation decrease in test scores for the average student, with potentially larger effects for allergic students. Supporting the reduced form estimates, the effect is somewhat more pronounced in subsamples with higher prevalence rates of hay fever. Additionally, I find that an increase in the ambient pollen level across exams reduces the probability that a given student graduates on time, and enrolls in higher education. An implication of these findings is that random increases in pollen counts can temporarily reduce cognitive abilities for allergic students who will score worse relative to their peers on high stake exams, and consequently be at a disadvantage when competing for jobs or higher education.