By fifth grade, children with early attention difficulties had lower grades and reading achievement scores than their peers. As fifth-graders, children with early attention problems experienced average reading scores at least 3 percent lower than their contemporaries’ and grades at least 8 percent lower than those of their peers. This was after controlling for IQ, socioeconomic status and academic skills at school entry.

Although these may not seem like large effects, the impact of early attention problems continued to reverberate throughout the children’s academic careers. Lower reading achievement scores and grades in fifth grade contributed to reduced grades in middle school and thereby contributed to a 40 percent lower high school graduation rate.

Source: Attention problems in early childhood can have lasting impact: Children with attention problems in early childhood were 40 percent less likely to graduate from high school, new Duke study finds — ScienceDaily