Thursday, September 24, 2009

To spank, or not to spank

It's an ongoing question, and constantly generates much heated discussion.

And I have no doubt, much more "heated discussion" (flame wars, really) will follow the latest round of news articles about a study by noted anti-spanker Murray Straus, such as this one from Yahoo! Children Who Get Spanked Have Lower IQs.

The title is the first obvious flaw. The study of course, shows nothing of the sort. The study is a typical correlative study that PROVES NOTHING. Dr. Eades has done tremendous work educating the public about the danger of mining "facts" from observational studies. Interestingly enough, in this article the journalist and the study author himself, readily admit the limitations of this type of study.

But while the results only show an association between spanking and intelligence, Straus says his methodology and the fact that he took into account other factors that could be at play (such as parents' socioeconomic status) make a good case for a causal link.

Still, it didn't keep statements of assumption and fact from headlining the story.

The study, involving hundreds of U.S. children, showed the more a child was spanked the lower his or her IQ compared with others.

What the study actually showed was a correlation between spanking and relative IQ.

The researchers tested the kids' IQs initially and then four years later.
Both groups of kids got smarter after four years. But the 2- to 4-year-olds who were spanked scored 5 points lower on the IQ test than those not spanked. For children ages 5 to 9, the spanked ones scored on average 2.8 points lower than their unspanked counterparts.

Note that is just a relative difference, it says nothing about comparison to baseline intelligence levels.

As Dr. Eades put it "It all seems so reasonable and so scientific, but the truth is that these studies don’t mean squat."

To most reasoning people, that is.

Whether or not spanking equates with dumber kids is not known, and may never be known. That's because the only way to truly show cause and effect would be to follow over time two groups of kids, one randomly assigned to get spanked and another who would not get spanked. Barring that method, which is unfeasible, Straus considers his study the next best thing, as he looked back at a nationally representative set of kids who were followed over time.

The author of the study knows it doesn't mean squat, but is bound and determined to sell his study and push his agenda (yes, Murray Strauss has an agenda)

Next best thing? Sorry, that is not how science works. If you can't do a scientific study, then you do not have any scientific evidence, no matter how much correlation you have done. Period.

According to Dr. Eades, studies like this do have the value of generating hypothesis.

The observational study demonstrates a correlation. In our example above, the correlation is that higher vitamin C levels correlate (in this particular study) with lower rates of colds. So, from this data, we could hypothesize that vitamin C prevents the common cold. But at this stage that would be just an hypothesis – not a fact.

Once we have the hypothesis, we can then do a randomize, placebo-controlled trial.

Except, when it comes to behavior, they can't. That's not to say there are never any "gold standard" behavioral studies, there have been some, mostly on animals, and mostly on benign stuff like pigeons pecking at a bar. But studying discipline, in a "gold standard" way? Very difficult to do ethically.

So while a lot of people with degrees after their names spend a lot of time telling you how to raise your kids, just look for the real science behind their ideas.

That's what a smart kid would do.

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