For my readers who enjoy discussing education questions, here's another, courtesy of Dylan Matthews at Vox:
The pre-K study was conducted by researchers at Vanderbilt University and looks at Tennessee Voluntary Pre-K, or TN-VPK, which has existed in some form since 1996 and offers many 3- and 4-year-olds free access to pre-K services. The actual pre-K sites were often oversubscribed, and had to resort to random lotteries to pick enrollees. The researchers exploited that feature to track students who were randomly able to enroll in pre-K in 2009 and 2010, and compare them to students who, by random chance, couldn’t enroll.
In prior work the same authors found that kids who got into pre-K outperformed ones who didn’t on intelligence tests — when they were 5. By the end of kindergarten, however, the benefits seemed to evaporate and by third grade, the pre-K kids were actually doing worse, with lower test scores in math and science.
This part is, I think, pretty well attested; most studies done over the past 30 years have found that Head Start and similar programs have positive effects, but those effects wear off quickly.
The new study follows the same children through sixth grade, adding three more years of data. The upshot? the results just keep getting worse. Reading, writing, and science scores in sixth grade were all lower among pre-K kids than other kids, and the gap has grown since third grade. The researchers also found that pre-K kids were likelier to skip school or get into disciplinary trouble as they got older.
Why? They don’t really know. The answer might depend on what the students who weren’t in the pre-K program were doing. The authors report that 63 percent were at home with a parent, relative, or other caretakers, and 34 percent were in private day care or Head Start. So you can read the study as suggesting that being home with a parent, grandparent, or nanny is better than going to pre-K; or maybe what’s going on is that Head Start and private care are better for kids than the Tennessee program. It’s hard to say.
But this isn’t just one study. Research into Quebec’s day care program found long-run negative effects on kids’ behavior, including increased crime. The idea that certain forms of pre-K or child care can harm kids has significant empirical support.
I wouldn't call this "significant empirical support," but it certainly is interesting.
For one thing, we might consider that "Pre-K" can mean a wide range of different things. What children do at a nice Waldorf program in an expensive area, lots of outdoor activities and organic baking and so on, might be very different from what happens at an underfunded Head Start program in a tough urban neighborhood or an Appalachian town. This is my beef with "Universal Pre-K" as a nationwide program; who can say what those programs will be like? If I, as a parent, think the local program sucks and my child will be better off at home, will that be a problem? Or will I have to file some kind of lesson plan like a homeschooling family has to? Can my lesson plan just say, "My child is 4 years old and will do 4-year-old things"?
There is also the question of children as individuals. Some might love preschool, others might hate it, and who knows what sort of long-term effects could arise from forcing 4-year-olds to go every day to a place they hate?
I understand what drives the push for more schooling. American children from poor and minority backgrounds seem to be falling farther behind the upper middle class on a bunch of metrics: IQ, test scores, college attendance, future income. It seems like the worldwide economy is changing in ways that make education more and more essential. Plus, finding care for their children regularly shows up as the biggest stressor in the lives of poor families and single mothers.
But forcing children to spend ever more time at schools that don't seem to be teaching them very much strikes me as a very bad strategy.