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A New Explanation For the Plight of Winter Babies 276

Posted by kdawson
from the prom-night dept.
Ant passes along a Wall Street Journal report on research that turned up a new explanation for the lifelong challenges experienced by winter babies. "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... 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. ... [Economist] 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." Here's a chart in which the effect — small but significant — jumps out unmistakeably.
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A New Explanation For the Plight of Winter Babies

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  • Jumps out? (Score:5, Informative)

    by ucblockhead (63650) on Saturday September 26, 2009 @03:42PM (#29549873) Homepage Journal

    Of course the difference jumps out. The chart was deliberately designed to make the change jump out by not using 0 as the origin of the Y axis.

    This is a very common technique for making a difference look a lot larger than it actually is.

    • Re:Jumps out? (Score:5, Informative)

      by wjh31 (1372867) on Saturday September 26, 2009 @03:48PM (#29549913) Homepage
      Much more important is the lack of error bars, they are what you can use to decide if the difference is greater than noise. However since they seem to be confident enough to include a secondary maximum and minimum, we are led to assume that the error bars are rather small. Since TFA says the study looked at 52 million children over 12 years, it sounds fairly reasonable to suggest that error bars are relatively small w.r.t atleast the primary max an min.
      • Re:Jumps out? (Score:4, Interesting)

        by ucblockhead (63650) on Saturday September 26, 2009 @03:51PM (#29549935) Homepage Journal

        Yeah, I have little doubt that there is a real effect here, but I hate when things like this are sensationalized. There may well be an effect, but it is a small one.

        • Re:Jumps out? (Score:5, Insightful)

          by AliasMarlowe (1042386) on Saturday September 26, 2009 @04:27PM (#29550135) Journal
          Did they use only data for Northern hemisphere women (north of the tropics)?, Or is it a mix with tropical and Southern hemisphere as well?
          • by TimSSG (1068536)
            I would guess that it is for the USA and the results is as one might expect based on the traditional school year in the USA. Me and my siblings were born during Oct(10) through Jan(01) because we were from a farming family. The down time for farmers is after harvest and before planting. Late Oct(10) to March(03). A School Teacher Family would try to target Late May(05) to early Sept(9) as the time to have Kids. Tim S.
          • Because there isn't a -1 "Didn't RTFA" mod.

            The article clearly states that it was (almost) all U.S. births during a certain time-frame, data courtesy of the CDC.

          • They used CDC data - that's the USA's Centers for Disease Control and Prevention. They're all Americans.
      • Re: (Score:3, Insightful)

        by Anonymous Coward

        Noise wouldn't be periodic.

        • by wjh31 (1372867)
          no, but if the amplitude of the oscillation you are trying to measure is comparable to the amplitude of noise, you would be foolish to try and draw many conclusions about that oscillation, certainly without any error bars. Also, there are plenty of sources of periodic noise, mains noise at 50/60hz is the prime example, but being periodic, its easy to account for.
        • Re: (Score:3, Informative)

          by metlin (258108)

          Noise wouldn't be periodic.

          Says who? Anyone who's done any kind of signal processing can tell you that there are any number of noise functions that can be periodic in nature.

      • Maybe the person that made it had a January birthday?(or June for our friends south of the equator)
      • by ceoyoyo (59147)

        Never trust a graph without error bars. But the pattern does look remarkably robust from year to year, which suggests that the noise is actually too small to be seen.

      • Re:Jumps out? (Score:5, Insightful)

        by icebike (68054) on Saturday September 26, 2009 @05:20PM (#29550525)

        From TFA:

        The two economists examined birth-certificate data from the Centers for Disease Control and Prevention for 52 million children born between 1989 and 2001, which represents virtually all of the births in the U.S. during those years. The same pattern kept turning up: The percentage of children born to unwed mothers, teenage mothers and mothers who hadn't completed high school kept peaking in January every year. Over the 13-year period, for example, 13.2% of January births were to teen mothers, compared with 12% in May -- a small but statistically significant difference, they say.
        --end-quote

        So problem is more than adequately explained by being born to a teen mother, and winter birth need not be related at all.

        Winter birth is probably attributable to spring break, and the re-emergence of summer fashions (read: skimpy) and horny young guys after a hard winter.

        The real story is births to teen mothers burdens not only the mother, but also the baby. Winter has nothing to do with it.

        • Re: (Score:3, Insightful)

          by maxume (22995)

          Yes, that is the real story. However, there has long been a mystery surrounding why winter babies do not do as well, and the fact that they tend, slightly, to be the children of teen mothers is an interesting explanation (hence the research and the article in the newspaper...).

          • by nametaken (610866)

            I found it more interesting that teenage pregnancy appears to be steadily declining and years of education steadily increasing. ...unless I read that wrong?

        • by T Murphy (1054674)
          So they need to look at teen births only to look for patterns. It would also be a good idea to look at only winter births just to confirm whether the teen births are the ones sticking out like this (probably true but they have the data so no reason to assume anything).
        • "horny young guys after a hard winter."

          Just curious - are you old enough to remember a hard winter? I'm 53, and I only remember a couple of them.

          As for the "horny young guys" - I never noticed that to be a seasonal phenomenon. Receptive, fertile females might be seasonal, but horny guys certainly are not.

          • by mini me (132455)

            How do you define a hard winter?

            On the 43rd parallel, which isn't even very far north as far as winter is concerned:

            - In the winter of 2000 it started snowing in mid-November and it did not stop until February.
            - In the winter of 2004, daytimes highs hovered at no more than 30 below zero for several weeks.
            - In the winter of 2007, the snowbanks could easily touch the powerlines.
            - Fifteen feet of snow was the official recorded accumulation amount for the winter of 2008.

            I mean, as an avid fan of winter, those j

            • by Hadlock (143607)

              On the flip side, the southern US experiences "snow" perhaps 22-30 hours a year. Does this study account for "hard winters" here in Dallas where we saw 48 hours of snow, before it got back up into the mid 60's?

      • Re:Jumps out? (Score:5, Insightful)

        by Rob the Bold (788862) on Saturday September 26, 2009 @06:16PM (#29551043)

        Much more important is the lack of error bars, they are what you can use to decide if the difference is greater than noise. However since they seem to be confident enough to include a secondary maximum and minimum, we are led to assume that the error bars are rather small. Since TFA says the study looked at 52 million children over 12 years, it sounds fairly reasonable to suggest that error bars are relatively small w.r.t atleast the primary max an min.

        TFA also says that the 52 million children in the sample were all of them, making the sample 100% of the population. That should result in some pretty small error bars, indeed!

        The two economists examined birth-certificate data from the Centers for Disease Control and Prevention for 52 million children born between 1989 and 2001, which represents virtually all of the births in the U.S. during those years.

      • Re:Jumps out? (Score:5, Insightful)

        by pla (258480) on Saturday September 26, 2009 @07:44PM (#29551655) Journal
        Since TFA says the study looked at 52 million children over 12 years, it sounds fairly reasonable to suggest that error bars are relatively small w.r.t atleast the primary max an min.

        With an n of 52 million, those charts do include error bars - They fall about +/- a thousandth of a pixel around each plotted point. The pixels themselves just cover the error bars.

        As for the Y-offset... Yes, you can use that to dishonestly highlight minor difference. When you have such small differences in your dependent variable, however, as long as you make the Y axis entirely clear to the reader, it merely serves to save the viewer a trip to find a magnifying glass.

        Basically, if you had a series that showed some degree of noisy periodicity and you zoomed/cropped in on one section that appears to prove your point, it counts as dishonest. When you have virtually no error and a trend that looks like cookie-cutter copies from year to year - I'd love to see the p values for this, but I'd bet it would require scientific notation to realistically print (ie, on the order of p <= 10^-12).
    • No... the effect can be statistically significant without being large. Of course the charts look more dramatic if you "zoom in", but the fact that the difference is only 0,5 % does not make it insignificant. And with the sample size of 52 million children, the results are probably very significant (too bad the article seems to omit the p-value for the tests).
      • Re: (Score:3, Insightful)

        by ucblockhead (63650)

        It's the being overly dramatic part that I object to. The difference may be significant, but it is small enough that in practice it means little for individuals. It's this kind of thing that has parents doing idiotic things like trying to conceive their kids in September so that they do better.

        • Re:Jumps out? (Score:5, Informative)

          by selven (1556643) on Saturday September 26, 2009 @05:11PM (#29550475)
          It's well known that children born in Jan/Feb/Mar are much more likely to get ahead because age cutoffs tend to be January 1, so kids born on Jan 1 compete with kids born on Dec 29 in the same year despite having 11 months more experience. Because of this, more attention is given to these "stars", and they perform higher. You should look at the birth months of some professional football teams.
    • Re:Jumps out? (Score:4, Insightful)

      by quantaman (517394) on Saturday September 26, 2009 @07:30PM (#29551563)

      Of course the difference jumps out. The chart was deliberately designed to make the change jump out by not using 0 as the origin of the Y axis.

      This is a very common technique for making a difference look a lot larger than it actually is.

      Or it could just be that using 0 as the axis would make a very unreadable graph that wasted a lot of space and didn't show the interesting portion very well.

      Clearly reducing the range has the unfortunate side effect of falsely increasing the perceived significance of the results. However, given that the graphs also very clearly print the mins and maxs I'm strongly drawn to believe that the researchers where actually trying to communicate the data accurately as opposed to tricking unwary readers.

      Oh, and the differences here are a 2.3% decrease in the percentage of married mothers and 1.2% increase in the number of teen mothers. Considering the topic they're analysing the effect is a lot larger than I would have anticipated.

    • by Lesrahpem (687242)
      The difference really jumps out with me. No allergies, walked at 9 months, IQ 168. Yeah, Winter really screwed me. Morons.
  • by Trepidity (597) <delirium-slashdo ... g ['kis' in gap]> on Saturday September 26, 2009 @03:44PM (#29549885)

    People have been debating this explanation for decades, and studies are all over the map. It'd be more accurate to say that there is yet another new study on the subject of the relationship between season-of-birth correlates and socioeconomic factors, this one claiming that the relationship is in fact significant. There's a bunch more [google.com] studies if you'd like [google.com].

    • The zodiac holds the most obvious relationship. Everyone knows Geminis are smarter than Aquarius folk. It's in the stars.
  • That means... (Score:5, Interesting)

    by Anonymous Coward on Saturday September 26, 2009 @03:44PM (#29549887)

    There's a tendency for promiscuous, uneducated teenagers to have unprotected sex during springtime and early summer. It's always easy to say this, but, duh...

    • 'duh...'?

      You're on slashdot, we've never even gotten close to those 'promiscuous, uneducated teenagers', except in our fantasies.
  • by craklyn (1533019) on Saturday September 26, 2009 @03:46PM (#29549897)
    Any measurement made requires two peices of information: the measurement and the uncertainty associated with that measurement. To present data as though its known with 100% certainty is misleading and incorrect. It seems pendantic to worry about uncertainty, but when you're dealing with small effects on the order of less than one percent, if the error bars are +/-2.5%, then it's absolutely incorrect to refer to the result as "jumping out".
    • You mean, error bars to measure how bad the counters were at counting?...

      1... 2... 3... 5... 6... oh... wait... shit
  • And Yet another (Score:2, Insightful)

    by TheBilgeRat (1629569)
    doctoral thesis claims their "significant" find is "significant". sigh.
    • by qw0ntum (831414)
      Pray tell, what else do you expect them to say? "Our research doesn't really show any results to speak of... but here's a paper anyway!". Also, statistical significance is, well, significant. So they are accurate in saying it is a significant finding.
  • Different metric (Score:5, Interesting)

    by HangingChad (677530) on Saturday September 26, 2009 @03:53PM (#29549959) Homepage

    If you count backward from January, that puts conception around April/May. Right around graduation. So if you suppose the poor and less educated would be getting married and starting a family instead of getting ready for college, that might explain some of it.

    It would probably be just as interesting to track the birth rates correlated to surges in beer and Jagermeister sales.

    • Actually, April/May is more like the lead-up to finals. People who are going to get a better education are probably a bit busy during that time.

      Doesn't change your point, though.

      Also, wasn't there a surge in births after the big black-out in New York?
  • 3rd bump (Score:2, Interesting)

    by danlip (737336)

    There is a secondary bump around September in each of these charts - it's much smaller but consistent every year. Fascinating.

    • Re: (Score:3, Insightful)

      by wellingj (1030460)
      New Years and Christmas parties?
    • by temojen (678985)

      Christmas party conceptions. As opposed to the other two which are prom/graduation conceptions and back to school conceptions.

    • by WMD_88 (843388)
      New Years resolution: let's have a kid this year! Or something like that. (No, really, I read something to this effect this past January. It's bound to pop back up in the media come the end of this year.)
  • by Anonymous Coward on Saturday September 26, 2009 @03:59PM (#29549987)

    The real causative in winter babies is that babies born under winter's astrological signs have shorter lifelines.

  • by Bwian_of_Nazareth (827437) on Saturday September 26, 2009 @04:03PM (#29550009) Homepage
    I see the explanation in the fact that married and educated women have sex with their man only once a year during their holiday in July/August. :)
  • Winter where? (Score:4, Interesting)

    by xirusmom (815129) on Saturday September 26, 2009 @04:07PM (#29550031)
    I wonder if all the data comes from the North Hemisphere? What happens in the south?
    • These bumps change shape in the southern hemisphere because health and success are much more closely correlated to the quality of available water in the region where you're born and grow up.
  • by e9th (652576) <`e9th' `at' `tupodex.com'> on Saturday September 26, 2009 @04:11PM (#29550053)
    The age cutoff for entry to kindergarten seems to cycle around mid-September, but varies quite a bit from state to state. [ecs.org] But in general, a kid born in the winter will have to wait longer to start school.
    • by eh2o (471262)

      They should have spring admission to kindergarten! November baby here and I'm about a year older than most of my classmates.

    • by Mashiki (184564)

      I was born in December. I started 3mo early, my parents rammed me through. But I don't live in the US either, I believe their words were something to the effect of "3 months doesn't make a difference when you're already at that curve."

    • Re: (Score:3, Interesting)

      by alex_guy_CA (748887)
      I though that it was better for kids to be the older ones in their class. Is there research about this? I just started my daughter in K late instead of early (November birthday) thiking being older would help her excel.
    • by msimm (580077)
      Heh. Does that mean that winter babies would tend to be physically larger then their spring counter-parts? With the spring babies beginning earlier having less physically developed frames?

      Do winter babies get picked more in dodge-ball?

      Once and for all, have we discovered the true source of the jock/nerd divide! ;-)
  • by Like2Byte (542992) <Like2ByteNO@SPAMyahoo.com> on Saturday September 26, 2009 @04:15PM (#29550071) Homepage

    Anyone else picture this guy screaming, "Get in my belly!!"?

  • by cinnamon colbert (732724) on Saturday September 26, 2009 @04:46PM (#29550257) Journal

    suppose educated women (and education strongly correlates wit income and wealth) "know" htat babies are supposed to be born in the spirng.....
    this would rduce the whole thing to a cultural artifact: well to do parents tell thier kids to have a spring baby, and so it goes...

  • by tthomas48 (180798) on Saturday September 26, 2009 @05:43PM (#29550711) Homepage

    People who plan their pregnancies are more likely to be educated, married, and not teenagers. People who plan pregnancies are not likely to try to target November - January, because it's cold and they won't want their babies birth close to Christmas and Thanksgiving.

  • Missing data? (Score:2, Interesting)

    by nurbles (801091)

    Did anyone else skim (or actually read) the 2008 paper by the researchers that was linked in the article? I notice many mentions of winter months and January but nothing about February or March (or the last week of December). In fact, the tables of data at the end of the paper list by month, but omit January, or by quarter of year, but omit the first quarter. What's the point of including data for everything except the two most mentioned time periods in one report?

    Something seems bogus to me.

  • They seem to put a kid as being disadvantaged for having a mother that completed high school in fewer years than her peers.
  • One of kids born the hottest day in 50 years, one born the coldest day in 80 years, one between - don't see any difference. Now, of course, if I would need research funds I might start seeing the differences - heh! Or maybe it was the size of the car in which they were taken home from hospital (need a car analogy in Slashdot) - have to start the research, just have to get maybe government funding for it.

  • When your wife gets to 7.5 months, take a 6 week vacation. You get to see some different fauna be it kangaroos, llamas or wildebeest. The baby is born during summer and has an exotic location on its birth certificate.

    Problem solved!

  • It's simple (Score:3, Funny)

    by Waccoon (1186667) on Saturday September 26, 2009 @08:42PM (#29552093)

    Birthday Blues! If my birthday was next to Christmas, I'd be depressed all the time, too.

  • Home Life. (Score:2, Informative)

    by MSUskater (1645071)
    I think that it depends on your home life. If you were born in the winter and your home life was tough such as you were raised by a single parent, or your parent are going through a divorce, or your parents education isn't real impressive then you probably won't be awesome in school because the good example isn't there. Sometimes financial struggles of the parent(s) can also allow for less access to good schools, good school materials, and a good education. Stress from home can cause a lack of motivation in

It seems that more and more mathematicians are using a new, high level language named "research student".

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