The Disadvantages of Summer Babies


A new report from the Institute of Fiscal Studies in the U.K. examines the big difference that a few months can make in the student achievement of young children. Authors Claire Crawford, Lorraine Dearden and Ellen Greaves found (along with several previous studies, like this one and this one) that children born in summer months generally score lower on standardized tests and are seen as “underachievers;” while children born in September and autumn months are more academically and socially successful. From a press release about the study:

Previous research published by the Institute for Fiscal Studies (IFS) has shown that children born at the start of the academic year achieve better exam results, on average, than children born at the end of the academic year. In England, this means that children born in the autumn tend to outperform those born in the summer. New research published today by IFS, and funded by the Nuffield Foundation, shows that month of birth also matters for other characteristics and outcomes of young people growing up in England today.  

The idea that small age gaps can have big impacts is nothing new. In fact, it’s something we write about in Superfreakonomics, with the birthday breakdown of European soccer players: 43 percent of players were born in the first thee months of the year, while only 9 percent were born in the final three months. Children who are a few months older than their peers at 5 or 6 have more developed cognitive and motor skills, which makes them more advanced athletes and students. This early advantage can lead to self-fulfilling prophecies later on: the child thinks she is an underachiever, and so will often play that role.  

The IFS researchers found some other startling statistics: summer babies are between 20 and 30 percentage points (2.5 – 3.5 times) more likely to be considered below average by their teachers by age 7, and are 7 percentage points (2.5 times) more likely to report being always unhappy at school. They are also 6 percentage points (twice as likely) to report bullying, perhaps because of their smaller physical size.

Co-author Ellen Greaves states:  “…the government should be concerned about the wider educational experience of summer-born children, who appear to be at a disadvantage in terms of their well-being as well as their test scores.” 

[HT: duffmanbrown]

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  1. Jim says:

    Elder and Lubotsky (Journal of Human Resources, 2009) also find that children with older classmates are more likely to be diagnosed with learning disabilities and ADHD than their peers. This is exacerbated by the practice of “redshirting” kindergarteners, in which more affluent parents who either need no child care or can pay for an additional year of private pre-K choose to hold their children back.

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    • Mike B says:

      Does that mean they can practice with the regular Kindergarten class, but not participate in any tests or competitions?

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  2. Dusan Vilicic Held says:

    What about people in the southern hemisphere? We have different dates to strart the school year, as well as reversed seasons. Maybe there is some interesting information to be found by analyzing the differences between both hemispheres

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    • MW says:

      Where I am in the southern hemisphere, we still have the same basic situation: summer holidays are mid December to end of January, the new school year starts in February (i.e. right after the summer holidays.) Other than shifting the month names, there is no difference (except that our summer holidays are about a month earlier than they should be, according to the weather, so as to fit Christmas/new year in at the beginning.)

      Of more interest perhaps would be Japan, where the start of the school year and the end of the summer holidays do not coincide. (I expect there are other such countries, but Japan is the only one I know of off hand.)

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      • teegee says:

        It doesn’t matter when the summer holiday is, just when the kids are born in relation to the start of the school year. Kids born in Japan Jan-Mar are said to be ‘born early’ & it is generally thought that those born in the first few months of the school year (Apr-Jun) ‘do better’…

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  3. Taylor says:

    Following the logic of summer babies being bullied, etc. because they are younger and less developed, shouldn’t autumn babies be even worse off? Shouldn’t it be autumn babies that are struggling instead of excelling as it says at the beginning?

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    • Mike B says:

      Yeah I am also a bit confused. Summer children will tend to be the oldest in any classroom as the cutoff date is in September or October for entry into school.

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      • Cari says:

        the cut off date in NY is December 1.

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      • stephenfnielsen says:

        In most states Summer babies will be the youngest of their classes because the cutoff date is in September.

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      • Enter your name... says:

        No, those cutoff dates make the summer babies young. Assume a September 1 cutoff date:

        If you’re born on August 31, your 5th birthday is the day before school starts. If you’re born on September 2, you are “too young” and thus have to wait another year — and when you do start Kindergarten, the second day of school is your 6th birthday.

        In the few schools that don’t use a cutoff date of approximately the beginning of September, you have to adjust the names of the months, but also (in America) you have to control for the socioeconomic class of the family. The cultural notion of being five years old on the first day of Kindergarten prompts better-off families to hold their children (especially boys) back if they would turn five in October or November, even though it would be legal to enroll them. Poor families send them ASAP, to reduce their child-care costs.

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      • Eric says:

        Policies change over time. The subjects in this study have to be older at then end of a longitudinal study as achievement is based over a lifetime, so policies may have been different than now, based upon information that had become available in the mean time. (had a research methods in social sciences class, as well as other related classes at university).

        I was an end-of-June baby and each academic year I was one year younger than the other kids in my grade level at school. I went into active duty military service directly after graduation at age 17, but started reserve duty at 16, less than a week after turning 16.

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    • Jessica says:

      Actually many fall babies still under the cut off are advised to hold their children back in pre-K for another year anyway specifically so they will not be behind developmentally/bullied for being younger. The same suggestions don’t often apply to summer babies because they don’t have a birthday during the school year, so they are less likely to be singled out for still being 4.

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  4. Zach says:

    Isn’t this more of a statement on how more care needs to be taken on how and when kids are grouped into categories? Isn’t 7 years old awfully young for teachers to be applying labels like “below average”? Seems like we could negate some of these problems if we would wait to divide the kids up until the age and developmental differences are minimized, like middle school.

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    • stedebonnet says:

      If the education system waited until middle school to divide kids it would be far too late (for that kid and everyone else in the class). If someone has a 60 IQ at 7, its unlikely to be higher at 12. But if you waited until middle school to place that student in a separate category, he or she wouldn’t be receiving the attention needed to improve and other students in the class would likely be held back by their performance.

      Its not really the education system “grouping” these kids. If teachers didn’t categorize these students, their peers would. The answer isn’t “lets not categorize kids.” The answer is for parents to wait until their kids are at least on level with their peers before sending them to school (developmentally, intellectually, emotionally, etc.).

      My mother, who has a MA in special education / child development and been in the field for 25+ years, has always told people with kids born in the summer to wait until their child was 5 (rather than 4) for school. Based off of her anecdotal experience and obvious differences in development speed, boys are more in danger than their female counterparts of falling behind.

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      • Enter your name... says:

        An anecdote to support the claim that if the teachers didn’t categorize the students, then the peers would:

        A young relative came home from Kindergarten some years ago and recited the names of all 25 kids in her class, in ranked order from “smartest” to “dumbest”. Her mother reported that the only factor apparently in the analysis was the classmate’s (perceived) reading skills.

        Importantly, being ranked low on the list didn’t make the classmate a bad person in any sense. The list was much less judgmental than if an adult had done this. The five year old seemed to think that ranking her classmates according to their reading skill level was really no different than ranking all the children according to their height or hair color.

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      • Kyle says:

        I had almost always been the youngest student in my class for the entirety of my academic career and it was something I took pride in. I was also always near the top of my class. BTW, I was born in the end of November, just before the December 1 cutoff in Michigan.

        If my parents had taken the advice to wait I would have been bored out of my mind by the slow pace of classes. I also would have had one less year of productive adulthood. So perhaps putting kids into school early is a good move for the economy.

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      • Eric says:

        From my own personal experience, I think your mother is quite right for a variety of reasons, which have nothing to do with academic success in my own case but social relationships based upon emotional experiences to do with things like relations to parents and other authority figures and peers, especially if there are other obvious differences that make the child stand out (especially in areas where tolerance, diversity, etc is not embraced).

        My experience derives from starting preschool at age 3, kindergarten at age 4, 1st grade at 5, etc. Even if mentally gifted, starting school earlier than peers can disadvantage a child when from an economically impoverished background where higher education might be perceived as being possibly better, but parents don’t know what is necessary to support it.

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  5. Mike B says:

    Having a child close to the end of the year also has significant tax advantages so people who plan their parenthood properly will shoot for a delivery date between October and December.

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  6. Megan says:

    Taylor- The autumn babies are the very oldest (assuming Sept. 1 or so is the cut-off date).

    Jim- I don’t understand…the children with older classmates? So the younger ones are more likely to be diagnosed? Either way, I don’t see how this would be exacerbated by “redshirting” it would just shift who is youngest and who is oldest.

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    • Enter your name... says:

      Yes, you’ve got it: So long as we only have one group a year, there will always be someone who is “youngest”. And so long as we permit voluntary redshirting, the gap in the children’s development will always be two full years, which exacerbates the teachers’ perception of the youngest as being young.

      If you had staggered school years (half the kids start in “September” and the other half in “February”), or even if you split the classes (so that the oldest kids were in one classroom and the youngest were in another), you would not have these perceptual problems.

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  7. Megan says:

    Taylor- The autumn babies are the very oldest (assuming Sept. 1 or so is the cut-off date).

    Jim- I don’t understand…the children with older classmates? So the younger ones are more likely to be diagnosed? Either way, I don’t see how this would be exacerbated by “redshirting” it would just shift who is youngest and who is oldest.

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    • Taylor says:

      Ok that makes more sense. Where I live in Canada the cutoff is Dec 31 (at least when I was a kid) so that’s why I was confused.

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    • Jim says:

      If all kids are “redshirted” you are correct that it would just shift who is youngest and oldest. But in the US, the kids who are redshirted are the ones whose parents have money — either to keep a full-time parent at home or pay for another year of pre-school/child care. When my May-baby entered first grade, he was nearly two years younger than the oldest kids in the class. And since the ADHD diagnosis relies heavily on a teacher survey, he appeared to be below the median on executive function and personal discipline. Partly because, it turns out, she wanted him to be medicated to make her job easier :(

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  8. Natasha says:

    Hidden due to low comment rating. Click here to see.

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    • MattN says:

      Obviously individual cases are largely influenced by proximal factors such as parental influence, but that doesn’t mean that other factors such as this have no effect at all.

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    • Mike says:

      I like how you disproved statistical evidence with a single anecdote.

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      • barrywhite says:

        correlation always – causation right mike?

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      • MattieShoes says:

        It’s obvious which direction causation flows — Poor school performance cannot affect your date of birth.

        I suppose it’s at least remotely possible that some other factor is influencing both (The chapter that mentions the link between Ramadan and health of children comes to mind), but age relative to peers in the classroom is a pretty obvious cause of differences.

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    • stedebonnet says:

      She’s also a girl. If your child was a boy (because of development), it might be an entirely different story.

      While parenting is important, there are physical and mental developmental stages that parenting can’t really impact. Nurture can help, but Nature has to be there too. I imagine if you’re child had a 90 IQ, you probably wouldn’t be making the same claims about “parents” being the key to it all.

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    • Jim says:

      Congratulations on being a standard deviation above the mean. I guess if you’d been in the sample, maybe they’d have reached a different conclusion?

      Yes, parenting has much to do with it. There are plenty of examples across the distribution of older kids who struggle, younger kids who excel, and everything in between. But controlling for other factors, younger children, and boys in particular, have a harder time.

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    • MattieShoes says:

      I don’t think they were trying to deny that parenting is a major factor. They’re saying age relative to classmates is ALSO a statistically significant factor.

      After all, the quality of parents probably doesn’t vary significantly based on what month they had their child. So if we accept that the average parent of a January baby is about equally good as an average parent of a June baby, and June babies do worse on average… Then the difference they’re seeing is not due to parenting.

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  9. Joshua Northey says:

    I love the work in this area because it helps demonstrate how striking the huge waste of human resources is on this planet.

    Either due to socio-economic status, factors like this with enrollment, or tons of other inefficiencies we are absolutely terrible at fitting people into tasks that suit them well.

    Surely the natural aptitude for playing soccer is distributed fairly randomly amongst the population, and yet we understand our HR processes so little that we end up with this type of distribution on the back end.

    It is the same in many other disciplines and is a huge waste of the most valuable resource on earth, cognitive ability.

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  10. ChuckFromAL says:

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    • Neil says:

      One local school mitigates this effect by shortening the age span of its classes for the first 3 years. Instead of having 3 classes each spanning an age range of 12 months, they have 4 classes each spanning a range of 9 months. With 3 terms per school year, children therefore move up a class every 2 terms rather than every 3. The school is very successful and massively over-subscribed, though I couldn’t say whether it’s for that reason.

      Other schools show no sign of copying the idea, though. It shouldn’t be too hard, since most of the schools near here have 2 or 3 classes per year group, each of which spans the entire year. Presumably it would be possible to have 2 classes each spanning 6 months or 3 classes each spanning 4 months and leave children in those groups for the first few years, with the aim of getting all groups to the same point by age 7 (what we call Key Stage 1 in the UK).

      I wonder if it’s been tried? And would it even help, or would it make the problem worse as the younger group suffers the tyranny of low expectations?

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    • Cari says:

      That’s not true, most states have different “cutoff” dates. As I stated above, NY cuts off on December 1, which happens to be my daughters birthday, hence, she started school at 4 1/2 years old, and is doing quite well, btw ; )

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  11. RobotKittyChan says:

    Malcolm Gladwell covered this a while ago in Outliers – NHL players’ birthdays are disproportionately in the first three months of the year. @Natasha, of course parenting plays a huge role in school performance. I personally am a summer baby, managed to score in the 98 percentile on the SAT, graduate with honors from an Ivy League school and go on to a successful career despite my “disadvantage”. It just goes to show how frightening it is that we as a society are wasting so much talent. Certainly there are plenty of Summer (and Fall, and Winter and Spring) babies who aren’t as lucky as I was or your daughter is to have parents in a position to offer so much guidance.

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  12. Sharon says:

    Did they correct for income? In the US at least, there are statistically significant differences in the income of the parents of children born in each month. The reasons behind this aren’t really understood, but ‘prom babies’ and poorer people trying to keep warm in the winter are some theories. Income could account for all of this.

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  13. Tina says:

    Just a random comment that may spark some dialogue. Many teachers plan to have their children during the summer so as not to interfere with the school year. My husband is a teacher and we targeted late spring/summer birth dates for our two most recent children (one still in womb). Does this mean our educators are setting their own children up for failure in the system they are the biggest advocates of? I’d be interested in seeing data on that.

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    • JSB says:

      …how does the current FMLA in the US factor into these choices people make (or try to make) is interesting data point. US is far, far behind in terms of parental leave – archaic really. What the potential downstream affect could be to children AND parents if gievn more appropriate leave (similar to other G7/G30/etc nations…)?? Years before 5 last the rest of their lives.

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  14. SAO says:

    The sports advantage is that kids who are bigger and more coordinated are better than their younger peers, hence get more play time. By the time a few months makes no difference, they’ve had a lot more play/practice time.

    Since most kids going to school get the same amount of teaching, regardless of success, you’d expect the advantage of being a few months older to fade over time. Is it still noticeable at age 10?

    In England, most kids start formal education with school work at age 4 (reception year), when 6 months is a big difference. Comparing with American kids and with Russian kids (who usually start at age 7), would be interesting, as it would point out to what extent the difference in 7 year olds is a result of the age difference at 7 and to what extent it is a carry-over from the age difference at 4 or 5.

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  15. Ruth says:

    I taught 1st grade before kindergarten was common. In Al. the children had to be 6 by Sept. In Fl. they could be 6 by January in order to enter school. Some parents kept their children out if they aren’t as mature as they needed to be. Makes a lot of difference.

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  16. Clay says:

    I think the reason this post is confusing everyone is because many readers are American, but the article is about the U.K. school system. In all five American school districts that I have lived in, the cutoff is December 31st. Thus, those students born in January are the oldest in their class.

    An American study with similar results would show that autumn babies (those born from October through December) actually have the lower test scores.

    A footnote clarifying this could have avoided a lot of confusion.

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  17. Stefan Richter says:

    For parents in the UK who are concerned and affected by this: I’ve started a Google Group in order to share advice and organise a campaign for a more flexible school start in England for summer born children.
    Please join, especially if you are a parent who has hit a brick wall with their local education authority. Let’s make change happen!



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  18. jenn says:

    This is only an issue if children start school too young. In countries that start school at 7, the rate of success is not pre-determined by the birth month. This is a proven case that starting school at the age of 4 is actually bad for some children. Why is the Uk so far behind in this way of thinking?

    Streaming is also a detrimental thing to do. When a young 4 year old is put in the lower group, it may take a few years for them to notice. But when they do, they feel badly about themselves and stop trying. Teachers slot children into categories and do not expect that they are capable of moving. When the lowest group continue to disappoint as under-achievers, the teachers can say to themselves,’ I told you so’. but the streaming is what keeps them there.

    It is a sad state when children are slotted into categories so young. Give them a chance for goodness sake! I am a very different person from when I was 4, as is everyone! Shouldn’t everyone be given the same chance to show they can grow up and achieve more if given a chance.

    Stop streaming and stop starting school so young. Let children play for a few years which makes more rounded and healthy adults!

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  19. Melina says:

    Where can I find the study that the European soccer statistic came from?

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