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A New Explanation For the Plight of Winter Babies 276

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.

  • by Trepidity ( 597 ) <delirium-slashdot@NOsPam.hackish.org> 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].

  • 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".
  • 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:Unwed mothers? (Score:3, Informative)

    by jonadab ( 583620 ) on Saturday September 26, 2009 @04:26PM (#29550131) Homepage Journal
    > Unwed? What is this, 1950?

    Statistically, the marital status of the parents is highly relevant to the child's prospects. Children whose parents are married to one another from prior to conception clear through until the child is an adult get on average much better grades in school, are significantly more likely to consistently hold down jobs as adults, make more money on average, are significantly less likely to have a criminal record, are less likely to be smokers, and so on and so forth. These are quite strong correlations.

    Now, correlation is not causation. It's possible that the parent's strong marriage does not *cause* the child's good prospects and performance, but rather that both are caused by some of the same socioeconomic factors. But it's still very much relevant in a statistical study like this.
  • Re:Anonymous Coward (Score:3, Informative)

    by ucblockhead ( 63650 ) on Saturday September 26, 2009 @04:32PM (#29550155) Homepage Journal

    Perhaps if you were born in May, you'd understand about significant, but small statistical differences and how they relate to the experience of individuals.

    Or to put it in more real world terms, you are like a woman reading an article saying "statistically speaking, the average man is four inches taller than the average woman" and saying "what crap! I'm taller than a lot of men I know!"

  • by ceoyoyo ( 59147 ) on Saturday September 26, 2009 @05:07PM (#29550435)

    Sigh. Correlation means one of three things with regard to causation. In this case those are:

    a) being born in the winter causes increased risk of health and education problems for the baby
    b) the baby's increased risk of health and education problems causes him or her to be born in the winter (clearly ridiculous)
    c) a third factor causes the baby to both be born in the winter and have increased risk of health and education problems.

    The correlation between birth month and risk of health and education problems has been observed. This study is pointing out that the direct causative option (a) is probably not true since they have found possible third factors (c) that appear to influence birth month and are known to have an effect on the risk of health and education problems.

    In other words, the study is saying, with actual data and without the childish, misunderstood slogans, the same thing you are - birth month does not cause increased risk of health and education problems.

    Showing correlation is required for establishing a causative link between two observations so no, correlation studies do not "need to die." It would be nice if people (including you) understood them a little better though.

  • 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:Born in December (Score:3, Informative)

    by ucblockhead ( 63650 ) on Saturday September 26, 2009 @05:27PM (#29550593) Homepage Journal

    Just to give an idea how silly individual data points are, here's what the data says in English:

    People who are born in January will get, on average, one month less education.

    Babies who are born in January are 10% more likely to have a teenager for a parent. (Note teenager means under 20)

    Babies who are born in January are 3% more likely to be born to an unwed mother.

    Interesting statistics, but the differences too small to really matter when comparing individuals. The fact that all of these measures aren't showing direct correlation with success but only correlations with other factors that correlate with success, any concern about when individuals are born is pointless. This study says little or nothing about what advantages a rich kid with married parents who is born in May might have over a rich kid with married parents who is born in January.

  • by pem ( 1013437 ) on Saturday September 26, 2009 @09:33PM (#29552387)
    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.

  • by ceoyoyo ( 59147 ) on Saturday September 26, 2009 @09:46PM (#29552447)

    If you'd like to post a link to the supposed correlation between Saturn and the S&P perhaps we can discuss it. Is it an actual correlation? You do know that correlation doesn't mean "has an r^2 greater than some arbitrary threshold", right?

    A correlation means that there IS a link between two things. An r^2 (or r) value indicates the strength of the aparent observed connection, and is also associated with a probability that the observed connection is not simply an artifact due to chance. Perhaps your Saturn-S&P "correlation" is simply that - a statistical fluke, perhaps born of someone doing multiple comparisons and not correcting for them. Actually, that seems extremely likely. I very much doubt someone purposely compared any feature Saturn and the S&P in a single, once-off test. By the way, what do you mean by "Saturn?" It's mass? Orbital period? Colour? The Roman God's independent living index?

    That is not what the study is saying. The author's of the study claim that it simply means that relatively more winter babies are born to unmarried and less educated mothers. The Wall street journal claims the study has found an explanation for the "lifelong challenges" of winter babies, as did the Slashdot summary. You've claimed something else? What will the tabloid newspapers claim? "Winter babies unhealthy, uneducated, unemployed?" How far do you think they'll go with it? When were you born?

    I don't know what the tabloids will claim (nor do I care), but the Slashdot summary is quite correct. They have found a new explanation for observed differences between winter and summer babies - the winter babies are more likely to be born of unwed, more poorly educated mothers. That explanation may not be THE explanation, but it is certainly AN explanation. I haven't done the background research to verify whether it is NEW or not, but it seems plausible. What part are you objecting to anyway? Perhaps you've confused the meaning of "explanation" with "absolute truth?" Maybe if you paid a little less attention to what the tabloids say....

    In other words, the study is saying, with actual data and without the childish, misunderstood slogans, the same thing you are - birth month does not cause increased risk of health and education problems.

    That is not what the study is saying.

    Actually, you're right. The study shows that there is a small remaining association between birth month and various outcomes, but it is very much weakened when socioeconomic status of the mother is taken into account. So really the study is saying birth month doesn't cause these outcomes, at least not to the degree that was previously believed.

    This study has not proved anything. It hasn't even suggested anything. It offers no reasoned explanation for its finding, with even the authors leaving such matters (proms and spring break) to the speculation of the reader.

    Actually, they have a whole section on possible explanations for why they see the trends they do, even though that is not the focus of their paper. They even use the phrase "prom baby" except that they have lots of references to actual research that has been done into the phenomenon. Of course, the actual point of their paper is to warn against drawing unwarranted conclusions from the season-outcome correlation, such as that the school intake system is unfair to winter babies. Wait... you did read the paper before you complained about it (and not just it, but condemned all of a large class of studies) right?

    This is a position which I fundamentally reject. Stephen Hales and Thomas_Young established causative and quantitative links before statistics had even been invented. Correlation is neither a neccessary nor a sufficient condition to establish any relationship between two variables. We cannot understand the world by computing correlation coe

  • Home Life. (Score:2, Informative)

    by MSUskater ( 1645071 ) on Saturday September 26, 2009 @09:54PM (#29552511)
    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 education.
  • Re:Jumps out? (Score:3, Informative)

    by metlin ( 258108 ) on Sunday September 27, 2009 @09:21PM (#29561337) Journal

    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.

Logic is the chastity belt of the mind!