Here is a great parental resource and Graphic from Living Sky School Division, Saskatchewan illustrating how by Grade 3, 58% of students with absenteeism of only 2 days per month can read at grade level versus 92% of good attenders who read at Grade 3 level.
Failing grades in English language is an early indicator by Grade 6 of early school leavers or drop outs in Destination Graduation: Sixth Grade Early Warning Indicators for Baltimore City Schools – Their Prevalence and Impact.