I'm happy that the article that Annette Hessen Bjerke, Elisabeta Eriksen, André Rognes and myself have published, is online. In it, we investigate how students' mathematics score correlate with whether they are born early or late in the year. The effect of being the youngest in a class seems to last for a long time.
Relationship between Birth Month and Mathematics Performance in Norway: (2021). Relationship between Birth Month and Mathematics Performance in Norway. Scandinavian Journal of Educational Research. Ahead of Print.