Young children labeled troublemakers because they pick fights on the playground or act up during downtime are not the most at risk of falling behind academically, according to several recent studies.

Instead, the students most at risk are those who from a young age have trouble paying attention, according to researchers. The findings come as a surprise to many educators, who have long connected bad behavior with bad performance in school. In time, the results could affect how attention disorders are caught and treated, both medically and in the classroom.