What cures poor sleeping habits of teens? Jobs.

It’s back-to-school season and time for the annual tradition of floating education policy ideas that no one really supports but that still get attention during the sleepy Labor Day weekend.

Exhibit A: The Rand Corp.’s new report suggesting that if public school start times were delayed to about 8:30 a.m., the higher academic performance of students combined with a reduction in morning car crashes would, after a decade, contribute $83 billion to the U.S. economy.

Additionally, the authors say, these economic gains don’t even take into account the wellness benefits we might see from better sleep for teens, including lower suicide rates, lower obesity and reduced incidences of mental health issues.

Have these researchers ever met any real high school students?

Myriad studies have shown that the No. 1 reason teens are up late at night is that they are on their phones in bed, texting and Snapchatting away into the wee hours.

My older son was clever enough to bypass the app I had installed to shut down his phone. As a result, he was falling asleep well past midnight with his phone in his hand and then getting woken up by his friends’ notifications throughout the night.

The high school students I teach are no different. Every year at the start of school, I ask them to fill out a survey. Many reveal that they’re either on their phones or video-game consoles until late in the night and feel exhausted in the morning.

I’ve taught at schools that started first period as early as 7:30 and currently am in a school where first period begins at 8:15. Yet I’ve observed very little noticeable difference between how the students arrive to school.

Across the five different high schools in which I’ve either substitute-taught or been a permanent teacher, the same pattern plays itself out: A small number of students come in so overly tired that they cannot function in first period, but most are as awake as any adults I’ve worked with at jobs that required starting before 9.

A select group have already been at school for well over an hour because they are in a club, choose to get extra help from teachers before school, or are out in the heat/cold, rain or snow training for a sport that requires before-school conditioning and after-school practice.

Students who succeed do so either by making the conscious choice to eschew their social desires and go to sleep as early as possible, or by toughing it out like every sleep-deprived teacher and office worker who stays up too late with babies, sick family members or the latest best-selling novel.

Most adults want more sleep — it truly is linked to lower body weight and better mental health — and wish their teens would prioritize it over other concerns.

But be prepared for a lesson in a cardinal rule of economics: Outcomes are predicted based on humans making rational decisions — and real, live humans interpret rationality in far different ways than researchers in labs.

Later start times would inevitably lead to later bed times.

How do I know? Like many public schools, my youngest son’s high school has a weekly, onehour late-start day.

And much like the students at the last high school I taught with a once-a-week late-start schedule, he and they would stay up about an hour later the night before and get the same amount of sleep as on any other school night.

You know what finally cured my elder son of his poor sleeping habits? Growing up and getting a paying job that required an early start time.

He figured out how to get the sleep he needed to perform his best in the morning — as all adults eventually do.