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.
Jumps out? (Score:5, Informative)
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.
this isn't a new explanation (Score:3, Informative)
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].
Measured data includes uncertainty (Score:3, Informative)
Re:Jumps out? (Score:5, Informative)
Re:Unwed mothers? (Score:3, Informative)
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)
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!"
Re:Correllation is Not Causation (Score:5, Informative)
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)
Re:Born in December (Score:3, Informative)
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.
They probably modded you flamebait (Score:3, Informative)
The article clearly states that it was (almost) all U.S. births during a certain time-frame, data courtesy of the CDC.
Re:Correllation is Not Causation (Score:3, Informative)
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?
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....
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.
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?
Home Life. (Score:2, Informative)
Re:Jumps out? (Score:3, Informative)
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.