They’ve made phone calls, sent out text messages, distributed fliers and hung banners. The message from area principals has been relentless and clear: Summer’s over. It’s time to hit the books.

Every year, thousands of students across metro Atlanta miss the first days of school. Some skip weeks. And it’s a problem.

Teachers spend the first few days of a new school year assessing where students are academically, establishing classroom routines and launching fast-paced curriculum. Students who start behind tend to stay behind, they say.

It’s not a new issue. There are parents who wait for paychecks to come before they send their kids back to school — so that they have money to buy school supplies. Some parents take their families on late vacations. And a lot of them, more than you might think, just plain forget. What? School starts before Labor Day now?

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Enough is enough, administrators say. With test scores and attendance mattering more than ever, administrators are throwing media campaigns and glitzy get-back-to-school parties featuring local stars and ice cream.

“Whether students show up on the first day really depends on the school’s outreach and the mindset of the parents in that community,” said Yngrid Huff, the executive director of Fulton Schools’ operational planning department.

At Banneker High School, the school’s teachers, cheerleaders and marching band plan to board a bus and ride out to local apartment complexes to welcome students back to school. Classes in Fulton start this Monday.

“We’ll just come out to them and stop waiting for everyone to come to us,” said Glynis Jordan, the school’s new principal.

Just how bad is the problem?

At Banneker High, 107 students, or 6 percent of the school’s population, was absent on the first day last year. At DeKalb’s Chapel Hill Elementary, almost a quarter of the school’s 562 students arrived days late. Osborne High School in Marietta had almost 10 percent or 200 students miss the first days of school.

Atlanta Public Schools grew almost 13 percent from in the first month of school last year.

Administrators use registration numbers and bit a eyeballing to gauge whether they have full house or if more students will be coming in the following days. Then they divvy up resources.

“What we want is for every student to have a book, desk and teacher,” Huff said.

When the numbers are off, administrators have to scramble last minute to relieve overcrowded classrooms and catch students up academically.

This year, Jordan said, teachers will compile folders of missed work for students who show up late.

Amid dramatic budget cuts, school boards have shortened school years and bumped starting dates, confusing many parents and interrupting family vacations, administrators say.

Victor and Angela Scott recently moved from Orlando, looking for a new start. It was by coincidence that they were driving down Barber Road in Marietta on Tuesday and saw a marquee at Fair Oaks Elementary announcing that school would start Wednesday.

Wednesday morning, Angela Scott was filling out last-minute registration forms for her son Isaiah. “He brought his backpack and his brain,” she said.

Principals say busy parents often hear school is about to start through their friends, social media or the news. Fulton and Atlanta held back-to-school media events to get the word last week.

Several schools held aggressive registration drives.

At Osborne High School in Marietta, parent liaisons called homes and passed out fliers at surrounding apartment complexes. At an open house Monday, two days before school started, students got a chance to meet their teachers and sign up for extracurricular activities. More than 1,000 people attended.

Principal Joshua Morreale introduced himself to new parents, hugged returning students and made sure he asked every students the key question.

“Are you going to be there on the first day of school?”