In his State of the Union address, the president came out in favor of warehousing youngsters for longer than ever. We know, insisted Obama, "that when students aren't allowed to walk away from their education, more of them walk the stage to get their diploma. So tonight, I call on every State to require that all students stay in high school until they graduate or turn 18."
Most states now allow students to drop out at 16 or 17. As a general rule, though, quitting high school restricts your options and reduces your income. Few adults would advise a youngster to leave without a diploma.
But general rules don't apply in all cases. The question here is not whether most students are better off finishing high school; it's whether the kids who otherwise would drop out are better off being forced to finish high school.
That's a very different question. Candidates who stay in the presidential race past April are far more likely to get the nomination than candidates who give up in January. But Rick Perry wasn't going to win even if he had stayed in till Christmas. If you're headed in the wrong direction, it doesn't help to keep going.
Why Obama floated the idea, with minimal explanation, is an open question. But the National Education Association, the country's biggest teachers union, has been pushing it. If you were cynical, you might think the union likes the proposal because it would mean more kids in school, which would mean more jobs for teachers, and that Obama likes it because the NEA endorsed him.
But even if their motives are pristine, it doesn't mean they are sound. The problem is that the youngsters who are most likely to drop out are the ones who are least likely to learn if they stay.
If they are 1) struggling to pass, 2) unwilling to apply themselves, 3) chronically tardy and absent or 4) simply not very bright, they won't learn much from being locked in a cell -- I mean a classroom -- for two extra years.
James Heckman, a Nobel laureate economist at the University of Chicago who specializes in education, is skeptical of the proposal. At the college level, he told me, "The returns to people who are not very able or not very motivated are typically quite low." There is evidence that kids may get some benefit from being required to stay in high school until 16 instead of 15, he says, but "it's a weak reed to lean on."
Let's also not forget that the highest dropout rates are in the worst schools. Even the kids who want an education often graduate from these schools barely able to read. Where does Obama get the idea that the reluctant students, compelled to remain, will reap a rich harvest of learning?
It might be argued that even if there is no benefit from keeping these students around till they turn 18, there can't be any harm. But think again.
The presence of disruptive, unmotivated kids in a class is a drain on teachers, a distraction to other students and a daily obstacle to learning. One of the best things you can do for students who want to do the right thing is to remove those who would rather goof off or make trouble.
It's not clear that laws like this will even work. A 2010 Johns Hopkins University study found that when six states raised the mandatory attendance age, three saw no increase in graduation rates -- and one saw a decline. Coauthor Robert Balfanz praises the 18-year-old mandate, but told The New York Times that "it's not the magical thing that in itself will keep kids in school."
If you want to keep unwilling students in school, you can spend money on truancy enforcement, which means taking money away from the willing students. It would be more rational to use the funds on education improvements so more kids will choose to stay.
A private company -- or a private school -- whose customers are fleeing has to come up with ways to keep them around. In Obama's public sector, there is a quicker solution: Lock the exits.