School's Out: The Role of Summers in Understanding Achievement Disparities

The field is generally aware of the summer learning loss (SLL) phenomenon. However key characteristics of SLL are not broadly established. What proportion of students’ school-year gains are lost in the subsequent summer? Is the magnitude of SLL generally similar across students or across grades? We describe the role summers play in the end-of-schooling achievement disparities using a unique dataset that spans eight grades, 200 million test scores, 18 million students, 50 states, and school-years 2008-2016. On average, 19% of students’ pathways from their 1st to 8th grade test-score occur during summers. We show that—even if all inequality in school-year learning rates could be eliminated, students would still end school with very different achievement due to SLL alone.