You already know that students who read over the summer perform better than their non-reading peers when school starts in the fall. But why? In a recent study at Harvard University, researchers tried to pinpoint what factors made summer reading so effective at improving performance. What they found surprised them.

It wasn’t necessarily access to books, the quality of literature, or even the number of pages read. The main factor leading to effective summer reading was involvement from adult family members.

In an earlier study, researcher James Kim and his associates found that the kids who read the most over the summer did the best on reading tests when they went back to school. But the researchers didn’t know why. In their more recent, larger study, they identified what made summer reading so effective.

“Our research indicates that it’s about more than access, especially with younger kids who are still learning to read,” Kim said. “Reading is most effective when parents or family members can provide reading guidance and make sure kids understand what they’re reading.” In other words, a little bit of involvement from adults—by helping students find the right books or by guiding reading comprehension with questions and  encouragement—can make a big difference, especially for students who are at risk for summer learning loss, like struggling readers.

The most important thing parents can do to help their kids get the most out of their summer reading is to follow the ABCs:

Access to books is basic, but important—and access to a wide variety of books is ideal. Check out our post on beating summer learning loss to find out how you can make sure your students have sufficient reading material over the break.

Books that match readers’ abilities and interests are key—if books are too easy or too hard, they won’t help the reader develop new skills or improve comprehension. Use the five-finger rule to find a just-right book for your reader.

Comprehension that’s guided by an adult, like a teacher or parent, is the most critical element in the summer reading equation. By asking questions, encouraging readers to ask questions, and guiding readers through difficult passages, an adult can help students improve their reading fluency and comprehension.

Check out this handout with 10 ways parents can get involved in their students’ summer reading efforts. Print it in English or in Spanish and send it home with your students before the school year ends.