Eighty percent of success is just showing up, comedian Woody Allen once said. That truism applies to all ages — but none more importantly than school children.

The Rowan-Salisbury School System has a 94 percent attendance rate, but behind the collective numbers is a subset of students who are chronically late or absent. Their parents or guardians fail to see how children are harmed when allowed to slip into this habit.

Superintendent Dr. Lynn Moody says the problem can start as early as kindergarten.

“We can feed them, we can teach them, we can even provide them school uniforms; but having them present and well rested are the two things that are extremely important for student success at school the next day,” Moody says.

To state the obvious, children who aren’t at school aren’t learning — and the resources available to them at school are being wasted. Early absences can lead to reading difficulties and snowball into poor attendance and poor grades in later years.

Data from 2013-14 found Rowan amid a cluster of counties with more than 10 percent of their students chronically absent, according a report, Preventing Missed Opportunity.

• Gaston County, 14.70 percent

• Rowan-Salisbury, 12.68 percent

• Iredell-Statesville, 11.79 percent

• Davidson County, 11.14 percent

• Cabarrus County, 10.45 percent

One California study found that only 17 percent of students who were chronically absent in both kindergarten and first grade were reading proficiently in third grade, compared to 64 percent of those with good attendance, according to Attendance Works.

Rowan-Salisbury students have begun their Thanksgiving break, so no one will be debating attendance for a few days. Parents who care about their children’s future, though, should spend some time thinking about the opportunity students miss when they lay out of school. Their children will never hear the words the teacher and other students shared in class discussions. They’ll never see that day’s lessons delivered; never take part in that day’s problem solving. That learning time is lost forever.

Some absences are unavoidable because of sickness or family crises. Parents should strive, though, for getting children to school and being on time every day. Don’t let one day missed lead to another day missed and another and another because it doesn’t appear to matter. The weekend will be here soon enough. Make every school day count. Otherwise, it’s lost forever.