The Prom Effect?

Researchers have long puzzled over the relatively poor health and education outcomes for babies born in the winter months. Past explanations have focused on school attendance laws, vitamin D exposure, and other environmental factors, but economists Kasey Buckles and Daniel Hungerman have found an overlooked explanation. They argue that less-educated women seem to have their children in winter, a fact that may explain some of the phenomenon. Our own Daniel Hamermesh says of the paper: “It means you have to think about things more than you want to think.” Buckles and Hungerman aren’t exactly sure why socioeconomic background drives the season of conception, but they offer the “prom” effect as one possible explanation: “January is, after all, about nine months after many of these soirées.” [%comments]


Aren't proms usually in May or June?

Kris Ronald Anderson

The one minor flaw in this theory is that most lower socio-economic kids don't go to the prom. That's a rite usually reserved to those that can afford the dress and tux. Most of them hang out somewhere at a party. But, I think the outcome would be the same.

karen lyons kalmenson

gives a whole new meaning for cinderella at the ball

David J Zaber

First things first: Given the increased physiological (and psychological) costs of somatic effort during winter months, it's not surprising that this mild selective force favored non-winter births.

However, before birth must come conception. Evolutionarily, there may be an advantage to being reproductively "ready" at all times yet that advantage would be tempered by the seasonal fluctuation in offspring survival.

The propensity for lower income women to have more babies in the winter months may be a result of seasonal changes stimulating hormonal shifts in men and women as the days lengthen. Or, poorer workers have a couple weeks of vacation that they take in the summer.....

You decide.


Were an overwhelming percentage of these babymommas 18/19 when they had thr babies?


Some sincere (and not so sincere) concerns with the conclusion....

First, are you calling Jesus, the ultimate winter baby, an underachiever?

If someone is going to the prom, that would tend to imply high school graduation, right? That's kind of a milestone in education. Should that be considered "less educated"?

Further, are these "winter babies" the offspring of recent high school graduates? If they are instead the offspring of, say, 20somethings, then it's not the "prom effect," right?

Maybe the March/April/May conceptions are due to people figuring out that they have an income tax refund coming, celebrating wildly and without protection (after all, they may figure they can afford a baby).

Or, since the conception months are some of the nicest months of the year, maybe folks are just experiencing "spring fever" and--viola! (These months also happen to coincide with Spring Break--where otherwise smart girls and boys get drop-dead stupid for a week.) More educated people don't experience this because they are too busy at their Goldman Sachs jobs to pay any attention to the weather (except how it affect commodity prices) and to notice the curves of the female fauna.

Of course, the REAL REASON is...St. Patrick's Day hook-ups. Drunken revelry appears to be an almost surefire way to conceive.



The point of the paper really isn't to argue for a "prom effect" but to note that quarter of birth or season of birth is non-random and likely correlated with unobservable factors that ultimately influence labor market outcomes. It's helpful to mention that there was a famous paper by Josh Angrist and Alan Krueger in the early 1990s that used quarter of birth as an instrument for schooling attainment, which given state mandatory schooling laws, would have resulted in some students receiving randomly more schooling since they would hit the relevant age cutoff sooner than others. That paper, and the many others like it, all argue that season of birth is basically random. This paper's main value is to call that assumption into question.


Wouldn't the prom only account for the first baby born to such a family? I mean you should only be getting knocked up at the prom once....


Hrm, I always thought that the November/December babies were a result of valentines day. I thought prom was generally in June, which puts the 9 months puts them in March . . .


maybe a "valentine's day" effect ?


Is there a difference in winter-baby health an education between the USA and other countries that do not have school proms or comparable traditions?


Why is our interpretation of these data (teens are a higher proportion of mothers for children in January) that there is a teen-specific cause for their birth rates to rise in January (and by deduction, conception rates to rise in April)? Why do we "blame" the teens?

It seems that it could be that birth rates for non-teen parents are disproportionally lower for these months, and we should be looking for the cause among the non-teens instead.

I looked at the paper and it appears that the chart on p. 29 suggests that there are differences between the profiles, but that the married folks are disproportionately low in the winter months. Blame them!

Mike B

The ideal time to have a child is between October and December. First this time is highly tax advantaged because a couple can claim a year's worth of deductions for only 1 or 2 months of actually having the child to care for. Second, it hits the middle ground in terms of cuttoff dates so that a child is neither the youngest nor oldest member of their class, both situations which are known to cause problems.

Denys Usynin

better educated women do better at family planning and can plan to have their children in a convenient month of July.


When young women have little or no education or job opportunities, they start looking for meaning in life. Often for poor women, that means a family. Women start to consider these options around the end of the school year, or near prom. By the time prom actually rolls around, they're probably already pregnant.

Unfortunately teenagers don't understand the risks and high chance of abandonment of relying on another flaky teenager to be a father and breadwinner.

And once you have a child as a teenager, it becomes progressively harder for a single parent to go back to school, gain skills or make the sacrifices to get ahead in an industry. If you have to pick up junior by 5:15 p.m., you really can't stay late to polish a report or work overtime.

As an anecdote, poorer women seem to believe that having a baby with a man will somehow cement that relationship. So they end up having more children with flaky men who leave anyway. It's a vicious circle.



Prom isn't the right time, but spring break is. Warmer temps, less clothing, alcohol, no school . . .


I'd say it is more likely Spring Break effect than prom. My old rural high school had prom in May, but it sounds like there is a wide variance in prom timing. Spring Break is more consistently in mid March-early April.


It could very well be in large part an epigenetic effect as well. Mothering during the winter months may be more difficult (as an example, it could coincide with seasonal affect disorder), which in turn may have an effect on the expression of relevant genes in the child. I couldn't tell on a quick scan of the article how much of the variance in winter baby health and education levels is due to the mother's education level but I'd wager the "prom effect" vastly oversimplifies what is going on. The authors acknowledge other possibilities but I didn't get a sense they tied it all together, really.

Ben D


"poorer women seem to believe that having a baby with a man will somehow cement that relationship."

That's not specific to poorer women. Trust me.


have they ever studied seasonal sperm differences in hitting the target or beyond conception seasonal differences in attachment to uterine walls? it's just not all about boinking and moment of conception.

centerfield affect?

c'mon it's about all those brown eyed handsome men :

beat the drum and hold the phone - the sun came out today!