What's the summer slide?

Summer slide is what happens between school years when kids and teens do not read, engage in learning activities, or otherwise work to retain what they learned in school.
On average, children lose approximately two months of their reading achievement if they do not read during the summer. They typically score lower on standardized tests at the end of the summer than they did on the same test at the beginning of the summer. And these few months of reading loss accumulate over the years. By the time kids reach middle school, those who haven’t read during the summers may have lost as much as two years worth of achievement!