What is Bedtime Math Really Good for?*

Attention conservation notice:  Short (500 words), but entirely misleading, though honest, criticism of actually really solid work on a great idea.  Take whatever time you were going to spend reading this, and use it to read Bedtime Math with your kids instead.

So, recently some very smart folks at Chicago published a fascinating study on the effectiveness of Bedtime Math, a set of math books and apps that encourage you to replace some of your bedtime story reading time with bedtime math reading time.  They find very encouraging results in an impressively large randomized field study (See Figure 1, reposted from the article).

Figure 1, reprinted from Berkowitz et al., 2015.

Unfortunately, their study suffers from a severe oversight. The authors failed to report on fully half of the most relevant data regarding Bedtime Math. A fuller examination including both sets of data should lead us to question the overall value of the intervention.  Clearly, I hate to accuse my colleagues (and in this case friends) of failing to report relevant data—a serious charge; I wouldn’t do so without extraordinarily good evidence.  But I happen to have excellent evidence.  You see, I purchased Bedtime Math several months ago, and read it with my children frequently.  I can say from this n=2 field study, that the Bedtime Math books clearly fail at their intended purpose.

It’s not that children don’t learn math from these books.  I have no reason to doubt the results presented in the article. No, no–The dangerous lie of so-called ‘Bedtime Math’ is in the first half of its name, as a brief examination of Figure 2 (which does not appear in the final version of the article) will show.

The figure you *didn't* see in Berkowitz et al, 2015.  Notice that in this graph, up is bad.

The figure you *didn’t* see in Berkowitz et al, 2015. Notice that in this graph, up is bad.

You see, kids just don’t go to bed after this “Bedtime” activity. First, the problems are funny, clever, and delightfully (for a 6 year old) gross.  Worse, math is an intrinsically active behavior.  Sure, when you read a story, a kid may have questions, add new ideas, and so on—but they can also enjoy the story while being quiet and still, snuggling and listening, gently drifting off to sleep.  Math isn’t like this.  You can’t do math unless you think, count on your fingers, wonder about new interesting things, suggest new and different problems, interrogate the structure of the situation—nothing that is even remotely like falling asleep.  Kids often love this kind of mathematical play, so it revs them right up, just at the time you’re ready to settle down for the night.  If the authors had included data on sleep-deprivation in the exhausted parents of Bedtime Math readers, they would have come to very different conclusions.

It’s too late for me: my son demands every night that we either reread Bedtime Math, or Bruce Goldstone’s equally engagaing books Great Estimations and Greater Estimations.  Neither path leads to sleep.  Please: save yourself.  Don’t buy these books.

A moment of seriousness

Obviously, I’m a fan of these books and this work.  I do believe, though, that there is substance in this observation.  We–both we the public and we the research community–often misunderstand the nature of mathematics, and think of it as something that is like reading, or like thinking.  It’s more like painting.  It’s an active, engaged process best done with a clear mind and on the move.  In its best moments, math is artistic, clever and funny.  I hope that beyond helping math anxious parents to help their children succeed in school calculations, books like these can help parents and kids access the delight that people who love math feel about it–whether in the morning or the evening.

* Update Notice: The original title of this post, “The Dangerous Lie of Bedtime Math”, was changed at the request of the Bedtime Math Foundation. I found their reasons compelling, and agreed to change it to something that would be a little less misleading out of context.  They also mentioned that Laura Overdeck DID successfully put her own children to sleep for many years with her drafts.

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