Marco Piovesan in bestseller

Daniel Pink’s “When: The Scientific Secrets of Perfect Timing” refers to Marco Piovesan’s paper published last year in PNAS.

Piovesan and co-authors identify one potential source of bias that influences children’s performance on standardized tests: the time at which students take the test.

Using test data for all children attending Danish public schools, between school years 2009/10 and 2012/13, they find that, for every hour later in the day, test scores decrease by 0.9% of an SD. In addition, a 20- to 30-minute break improves average test scores.

The Time of the day, affects students’ test performance because, over the course of a regular day, students’ mental resources get taxed. Thus, as the day wears on, students become increasingly fatigued and consequently more likely to underperform on a standardized test.

These findings, according to Pink, suggest that “scheduling in a couple of 10 or 15 minute breaks throughout the work day helps improve work performance. Breaks can include napping, taking a walk or spending time outside with somebody else. The key is to avoid bringing up work issues in order to practice full detachment from the work place.”