I found this article in the Daily Mail. I don’t post much in the way of newspaper articles. They tend to go the way of junk science, but this article made a good argument. As few as three absences from school can have a significant impact on student achievement on standardized tests. This same correlation might be extended to classroom assessments and academic progress.
A note to consider: correlation does not necessarily mean causation. There are multiple complexities in the lives of the students at the center of this study. Still, the point is a good one. The academic calendar is a deliberate mechanism designed to build understanding. Interruptions to plans, sequence and content delivery can and will result in diminished student achievement.
Enjoy the story.