Kids, Happiness and Bad Data

I was fascinated to read a story this morning discovering that “Mistakes in Scientific Studies Surge.” Research journals are reporting an epidemic of retractions. Scientific researchers are, alas, inclined to the same sorts of statistical errors and silly mistakes the rest of us make and, in an era when academics must publish or perish, the tendency to seize on a significant result, even if it doesn’t pass the smell test, is high.

I’ve been thinking about this because I’m also dealing with the fall-out from a study error, in this case in the area of social science. In my chapter on “The Marginal Cost of Children” in All The Money In The World, I cite a study from Scottish economist Luis Angeles showing that overall life satisfaction rises, among married couples, with the number of children.

This result made a fair amount of intuitive sense. Children do not boost moment-by-moment happiness; changing a diaper is less fun than watching TV. People stay in jobs they don’t like in order to feed, clothe, house and educate their children. But overall life satisfaction is a different matter. Among married couples in a society with widespread access to birth control (Angeles was looking in the UK), having a growing brood (up to the 3-4 kid level Angeles examined) tends to be a sign of a stable marriage, good finances, and a general sense that things are going well enough to bring another child into the world. Why wouldn’t that correlate with overall life satisfaction?

But Angeles later discovered a coding error in his data which removed any statistical significance to this finding, and muddled it completely. So he retracted the paper. I didn’t learn about that until now, so now I’m re-writing the chapter.

I think there is a circumstantial case that parents benefit from having more children (one of the tenets of economist Bryan Caplan’s book Selfish Reasons to Have More Kids; I’m now realizing the fact that Caplan didn’t tout Angeles’s study should have been a red flag!) For starters, people who have fewer children often regret not having more, as shown in this study released recently of male and female scientists at top research universities. There is also the well-documented fact that a strong social network increases happiness. Kids can’t be that network when they are little, but later in life they can be. Given that cost data from the USDA finds that the third child is much cheaper than the first two, this may tip the cost-benefit analysis. And some re-evaluations of the Day Reconstructive Method used to show that childcare doesn’t make people happy have found that, when you take into account what people think about what they are doing, they rate time with kids much higher (see Mathew White and Paul Dolan’s “Accounting for the Richness of Daily Activities,” in the August 2009 issue of Psychological Science, unfortunately not available in full text online).

But, of course, using something like social science data to look at what is a profoundly personal question is always a bit questionable. My own decision to go for a third kid was not about whether, averaged over thousands of individuals, a third child increases life satisfaction. It was more that I think my two little boys are awesome people and while past performance is no indication of future returns, I suspect I’ll like any other kids I have too, and on the margin they will make the world a better place. My main concern with motherhood was that it would come at the price of my writing career; since that has not been the case, that tipped the balance toward a bigger brood. It would be nice if there were social science data to back this up, but life is sometimes too messy to be quantified to a level of statistical significance.



17 Responses to Kids, Happiness and Bad Data


  1. Susan says:

    Congratulations on your third child! I agree that “life satisfaction” is hard to qualify and quantify. Parents may have to put up with temper tantrums; but if they get ill later on in life, they will have their children to take care of them.

    • Laura says:

      @Susan- Thanks! This is one of the calculations Caplan suggests in his book, weighing the pain of children when they are babies with how fun and helpful they are in later years. Obviously, just because you have kids doesn’t mean they’ll take care of you (one of the reasons old age poverty has always been an issue, and why various governments have come up with old age support systems, even if they are one of the reasons for our fiscal mess at the moment!) But if you have four kids, you’re certainly more likely to have some of them involved in your life later on than if you have zero.

  2. Jeremy says:

    I got Caplan’s book on your recommendation, but it isn’t ringing true to me. Seems like some pretty big blind spots and shaky logic. He mentions (but discounts) the numerous studies showing how having kids makes us less happy, then pins his entire thesis on his interpretation of a few studies of twins. However, I’m not finished yet, so I will have to reserve judgement.

    More kids can mean more help later in life, but that can go the other way too. It’s not uncommon for boomers to have two kids, have one of them disabled or struggling with mental health issues, and find that they’ve got an dependent in their household rather than someone to take care of them as they age.

    • Laura says:

      @Jeremy – well, yes, life is a wager. I don’t think anyone will *actually* decide to have more kids because of Caplan’s book, but it was a nice antidote to various popular press articles I keep reading about exactly what you need to do with your kids to make them come out a certain way. There is nothing you can do to guarantee your children will come out a certain way. The joke is that these books/articles are written for first time parents because, by the time you have the second, you realize that illusions of control are just that.

  3. Twin Mom says:

    It would be interesting to study parents who had a single child and then twins vs. parents who had two children and chose to have a third. This could help deconvolute whether people who like/can afford children have a third child or whether having more children makes you happier.

    I spent a month in the hospital before my twins were born (prematurely) and my joke to the social workers, etc. who asked if the baby was “planned” was “one of them was, one of them wasn’t. We aren’t sure who is who yet.” They asked because of the statistical correlations between unplanned babies, prematurity and poor life outcomes.

    Fortunately, we don’t live in a world where people can be randomly assigned to have more children or not so our data on this topic must remain observational.

  4. Congratulations on your third baby (and your new book)! I’m five months into being a first-time mother, and I can’t quite imagine quantifying this infinitely rewarding and relentless new experience.

    • …nor can I imagine having the brain space to write more than a two-sentence response, evidently!

    • Laura says:

      @Jennifer – that’s what I find so fascinating about attempts to measure happiness and other subjective things. We’ve long assumed it can’t be measured, but perhaps that’s not true. What we do know is that happiness is complicated, and moment-by-moment happiness is different than life satisfaction happiness. If we were only attempting to maximize moment-by-moment happiness we’d all be stuck in front of the TV eating potato chips out of the bag.

  5. Meagan says:

    Do you have a link to that data indicating that child #3 is cheaper than the first two? I was talking to someone about this today and I’d like to be able to share it with her.

    • Laura says:

      @Meagan: See this report from the USDA: http://www.cnpp.usda.gov/Publications/CRC/crc2010.pdf (Go to Table 8). Basically, your second two kids are cheaper together than the first. For a middle income family, the first kid is roughly $15-17k per year, second kid adds another $10k, but the third adds only about $4k.

      • Twin Mom says:

        I’ll bet the third child cost is due to childcare- at 3, you either have a stay-at-home parent (lost wages not included in USDA data) or hiring a nanny is cheaper than daycare for 3.

        • Laura says:

          @Twin Mom – Maybe, though I’m not sure what percentage of families wind up with 3 pre-school aged children (who’d need full-time care) simultaneously. On the other hand, the USDA stats always strike me as incredibly low for an average on childcare.

          • a different Cara says:

            I have anecdata! My parents had three kids under age 5 in daycare at once– me and two little brothers. I have no idea how it made financial sense, except that it was a tiny town and it wasn’t really a daycare at all. It was some other kid’s great grandma, and she literally sat around and watched t.v. all day while the whole herd ran wild. She didn’t charge much.

            Once my parents figured out what was going on, my mom quit her job. It was bound to happen eventually, because my parents ended up having six kids total (over the course of 11 years).

            I’ve noticed that in small towns (where people don’t really have access to nannies to hire), when people hit the “more daycare than salary” point, the women suddenly decide that what they really want, more than anything, is to open their own in-home daycare.

          • Laura says:

            @Cara- I absolutely love the word “anecdata.” I may have to start using that…

          • Twin Mom says:

            USDA data also has a strange way of calculating housing costs- they basically apportion part of the cost of the house to each child. Since most people live in the same house whether they have 2 or 3 kids, perhaps this is a factor.

            These studies are very hard to interpret- it’s like the time study saying that employed mothers spend only 10 hours less per week on childcare than mothers who are not employed. Well, that’s likely because the employed mothers are overwhelmingly mothers of older children (who handle their own dressing and bathroom needs) and the unemployed mothers have young children. The better question is, “How do parents of children *of the same age* differ in how they spend their time?” Under 18 is a broad range…

          • Laura says:

            @Twin Mom- true, under 18 is a huge range, though the American Time Use Survey does break it down by under 6, and then 6-17, to get at some of this issue. Of course, under 6 is a broad age range too, if you think about it. A 4 year-old in 5-day-a-week preschool is going to be different than a baby. But babies sleep a lot too. Suzanne Bianchi has done some fascinating research on this, that the difference between employed and not employed mothers even among the same age ranges is less than we’d imagine for a few reasons. First, children aren’t available to interact with 24/7 due to school, napping, independent play, activities, etc. Second, the average mother doesn’t work that much. Many women work part-time, and among those with full-time jobs and young kids the average barely tops 35 hours per week (indeed, the ATUS puts it a little lower — meaning people are defining themselves as full-time but aren’t actually putting in full-time hours for various reasons). So yes, a female law partner working 60 hours a week will see her baby less than a stay-at-home mom, but often the differences in how people live their lives are not as clear cut as that.

      • Meagan says:

        Thank you!