Does later test time or a break improve performance on standardized tests in children attending Danish public schools?
Taking tests later in the school day negatively impacts student performance due to cognitive fatigue, but a short break can mitigate and even reverse this effect.
Using test data for all children attending Danish public schools between school years 2009/10 and 2012/13, we examine how the time of the test affects performance. Test time is determined by the weekly class schedule and computer availability at the school. We find that, for every hour later in the day, test performance decreases by 0.9% of an SD (95% CI, 0.7-1.0%). However, a 20- to 30-minute break improves average test performance by 1.7% of an SD (95% CI, 1.2-2.2%). These findings have two important policy implications: First, cognitive fatigue should be taken into consideration when deciding on the length of the school day and the frequency and duration of breaks throughout the day. Second, school accountability systems should control for the influence of external factors on test scores.
Sievertsen et al. (Tue,) studied this question.