Kids and Costs: A Guest Post on Twins by Bryan Caplan


Bryan Caplan, a professor of economics at George Mason University and a blogger for EconLog, is the author of a new book called “Selfish Reasons to Have More Kids: Why Being a Great Parent Is Less Work and More Fun Than You Think.”  He’s guest-blogging for us about parenting.  You’ll  be hearing more from Caplan in these environs soon, as he’ll be one of the guests in an upcoming Freakonomics Radio show tentatively titled “An Economist’s Guide to Parenting.”

Kids and Costs
By Bryan Caplan

One day when my wife and I were strolling our twin infants, we overheard a passing jogger tell her friend, “Now there’s a reason to shoot yourself.” Econ 101 suggests that she had a point. Economists usually assume that doubling output more than doubles costs; or as textbooks say, there are increasing marginal costs. So economists naturally expect twins to be more than double the effort, stress, and out-of-pocket cost of a singleton. As Joshua Gans of Parentonomics writes: “But regardless of the level of the cost curve for parenting, it is surely the case that the marginal costs of parenting for each additional child are increasing.”

Econ 101 was brutally accurate for the first three months of our twins’ lives. I was in charge of midnight feedings, and repeatedly faced an ugly dilemma: What do you do if one twin wakes up for food while you’re feeding his brother? Either way, you have a baby in tears.  But as our twins grew up, Econ 101 gradually drifted away from the facts, for three main reasons.

First, after infancy, most of the cost of parenting is fixed. People with one child live very different lives than people with zero children: Parents move to the suburbs, rarely travel, and stay home Saturday nights. But once you make these sacrifices, an extra child has little additional effect on your lifestyle. Maybe that’s why almost all of the negative effect of kids on parental happiness in the General Social Survey comes from kid No. 1.

Second, doubling your kids definitely less than doubles the financial cost of raising them. Hand-me-downs and nannies are the most obvious examples. But the deeper reason is that parents learn by doing. Once you discover the Ferber method for making babies sleep through the night, you can use it over and over.

Photo: iStockphoto

Third, as long as your kids play well together, more kids can actually be less work. Now that they’re eight, I’m convinced that our two twins demand less attention than one singleton. Why? Because each twin has a built-in playmate. We don’t have to entertain them much because they entertain each other.

Ultimately, Econ 101 does have the last word: If you keep having kids, you’ll eventually reach the point of increasing marginal costs. That’s good to know. But it’s at least as important to realize that your second, third, or fourth kid won’t cost as much as your first — and might even make your life easier.