As school starts back up, students will again try to exaggerate their small coughs into a disease severe enough to warrant the highly sought-after sick day.

According to research released Tuesday by the Ad Council, about half of parents think it's okay for their child to miss three or more days of school per month. The official definition of "chronically absent" is a student who misses two or more school days per month, meaning that more than half of parents think it's okay for their child to be chronically absent.

"Even when excused or understandable, absences add up and can greatly impact a child's education," a press release from the Department of Education says. "In reality, missing just two days of school per month makes children more likely to fall behind and less likely to graduate."

Data from the department show that more than 6 million students miss at least two days of school per month, making them chronically absent. The problem seems to get worse as students age, with 10 percent of elementary students chronically absent rising to 18.7 percent of high school students.

Parents do seem to understand that attendance is important in school, with 86 percent saying "attendance plays a big role in helping [students] graduate from high school." But the general acceptance of missing three or more days a month implies they don't understand how little room for error there is.

To fight back, the Department of Education is teaming up with the Charles Stewart Mott Foundation and the Ad Council to create public service announcements that will inform parents how important attendance is and to help them ensure their student is in school every day.

Jason Russell is a commentary writer for the Washington Examiner.