Exploring the summer slide in the Netherlands

This study considers the existence of a decline of academic skills in the summer – the so-called “summer slide” – in the context of a relatively short, six-week summer holiday. It further proposes that the extent of this decline will be moderated by home-based practice, and that this practice itself is a function of student and context-level factors. To investigate these issues, a pre-post (summer) study on mental arithmetic was conducted in the summer of 2018 among 932 Dutch grade 2 children. The results demonstrate a sizeable summer learning loss, finding a 0.26 s.d. decline in performance post vs pre-summer. The effect is significantly ameliorated through observed practice on an online educational platform (Squla), but not through self-reported practice. In contrast, perceived competence, gender, and socio-economic status correlate with self-reported practice, but not with observed practice. We discuss the implications of these results for existing and future research in the literature.