I believe in the healing power of statistics. When threatening clouds blot my normally sunny skies I reach not for a glass of red wine but for a most unlikely elixir: the statistical principle known as regression toward the mean. While this dry doctrine may not sound like a good way to soothe oneself, I find it as consoling as Charlie Brown’s friend Linus finds his blanket.
Simply put, regression toward the mean states that extraordinary events are likely to be followed by more ordinary ones. Perhaps a couple of examples will help bring back memories of what you and I should have learned in statistics class. Regression toward the mean is often seen in sports and explains such seemingly inexplicable phenomena as the sophomore slump and the Sports Illustrated cover jinx. Extraordinary seasons or accomplishments, like great freshmen seasons or getting on a sports magazine cover, are likely to be followed by more ordinary ones as the player or team likely benefited from “lucky” factors, including fewer injuries, favorable scheduling or weak opponents. Since it is unlikely that the team will benefit from this mix of fortunate factors again it will, most likely, regress toward the mean or, more crudely, become more average. (Special note for Cubs fans: Regression toward the mean does not apply to your beloved team; I’m afraid that they will always be average or poor.)
My Eureka moment with regression toward the mean occurred 20 years ago when I read an article on decision-making errors. Do you know how some things immediately resonate with you? Maybe a poem or painting? This innocuous little principle immediately helped me make sense out of our sometimes nonsensical world.
With just a bit of practice you can see regression’s fingerprints everywhere. Do you think that the current administration is inept? Since most of our presidents have at least been average, your chances are good that the next one will be better equipped to handle the job. Are your basically happy kids having a meltdown? Chances are the tantrum won’t last long.
I guess what regression toward the mean really gives me is a way to minimize my fretting over smaller, less likely events; it helps me put things in perspective. It’s my statistical salve. Bad days are just that and not necessarily “the end of the world as we know it,” as R.E.M. sang. And that’s quite a gift from a dry statistical principle that I didn’t quite master in college.
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