Researchers Stumble Upon Alternative Explanation for the Lifelong Challenges Faced by Children Born in Colder Months
By JUSTIN LAHART
Children born in the winter months already have a few strikes against them. Study after study has shown that they test poorly, don’t get as far in school, earn less, are less healthy, and don’t live as long as children born at other times of year. Researchers have spent years documenting the effect and trying to understand it.
But economists Kasey Buckles and Daniel Hungerman at the University of Notre Dame may have uncovered an overlooked explanation for why season of birth matters.
On Autism, Snow, Scores and Streams
Read past WSJ stories that looked at controversies over the “natural experiment” approach:
* Is an Economist Qualified to Solve Puzzle of Autism?
(2/27/2007)
* Novel Way to Assess School Competition Stirs Academic Row (10/24/2005)
Their discovery challenges the validity of past research and highlights how seemingly safe assumptions economists make may overlook key causes of curious effects. And they came across it by accident.
In 2007, Mr. Hungerman was doing research on sibling behavior when he noticed that children in the same families tend to be born at the same time of year. Meanwhile, Ms. Buckles was examining the economic factors that lead to multiple births, and coming across what looked like a relationship between mothers’ education levels and when children were born.
“I was just playing around with the data and getting an unexpected result,” Ms. Buckles recalls of the tendency that less educated mothers were having children in winter.
video
Assigning an Apgar Score to Newborns
5:50
It’s said that “every baby born in a modern hospital in the world is looked at first through the eyes of Dr. Virginia Apgar.” In a 1964 video, Dr. Apgar assists a nurse through checking a newborn’s reflexes.
The two economists, whose offices are across from one another, were comparing notes one day and realized that they might have stumbled across an answer to the season-of-birth puzzle that previous research had overlooked.
A key assumption of much of that research is that the backgrounds of children born in the winter are the same as the backgrounds of children born at other times of the year. It must be something that happens to those winter-born children that accounts for their faring poorly.
In a celebrated 1991 paper, economists Joshua Angrist of the Massachusetts Institute of Technology and Alan Krueger of Princeton University argued that season-of-birth differences in how far children go in school is due to how school-attendance laws affect children born at different times of the year. Children born in the winter reach their 16th birthdays earlier in the year than other children, which means they can legally drop out of school sooner in the school year — which some do, leading to lower education levels in the group.
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