Friday, June 5, 2020

Flashback - Unbelievable Numbers?

[Almost a year ago I wrote about the statistics that politicians, pundits and experts spread without any support. They are repeated to the point where everyone accepts them as gospel, and no one bothers to check. It happens often. These are just a few that I highlighted at the time.]

Politicians and other entities trying to raise awareness to one or another kind of problem or injustice love to toss out surprising numbers to gain support for their cause. In many cases these are not real numbers. They could be based on data collected by the program itself with no effort to be unbiased, in fact, the more shocking the better. They may have been based on a single survey that made no effort to confirm results, and may directly conflict with the results of similar surveys. Like the unverified number of discarded plastic straws that was really based on a small survey for a grade-school project that led to such an uproar, the numbers are often repeated so many times by so many people that everyone assumes they are correct. 

With so many examples, how can we tell what to believe?

Everyone knows that ten thousand steps per day is the recommended amount to stay healthy and to boost longevity – or do they? This NPR piece tells us “the idea of walking at least 10,000 steps a day for health goes back decades to a marketing campaign launched in Japan to promote a pedometer” and is not some kind of magic number. In a recent study published in JAMA, older women who averaged 4,400 steps per day were better off than those taking only 2,700, with little or no benefit over about 7,500 steps. This finding was confirmed elsewhere.

The myth of 10,000 daily steps is akin to 8 glasses of water daily. There is no basis. Someone made it up. The best advice, to drink when you are thirsty, continues to be drowned out by the “hydration parrots” who swear by 64 ounces.

Other examples include the unacceptably high number of school shootings. The Campus Safety Magazine puts the number for 2018 at 82, “the highest there have ever been since 1970.” They mention that the second highest was 59 in 2006, so it can hardly be called a trend, perhaps more of a blip. They then state that the majority didn’t happen on school property – indicating a rather loose definition of school shooting. Compare that to the Wikipedia list of each occurrence by location with a total of only 36 for the same year.

Time article calls into question the widely circulated number of one in five women in the US having been raped. They call that number misleading noting “the striking disparity between CDC figures and the Justice Department’s crime statistics based on the National Crime Victimization Survey (which includes crimes unreported to the police).” This article provides much detail and there is room for doubt (as I pointed out earlier), yet we continue to hear the same number.

Of course everyone also knows that crime and teen pregnancy are worse than ever – not so fast! “Violent crime in the U.S. has fallen sharply over the past quarter century.” Here is a link to that Pew survey from earlier this year showing several graphs on violent and property crimes all heading in the right direction, although you’d never know it from the news coverage. That explains why the public perception is the opposite. Likewise a site called the Seeker reports, “the fact is that teen pregnancy is low and has been dropping.”

Can the recent increase in tornados be attributed to Climate Change? This article from a Carbon Brief posting calls it highly uncertain – with references to the data. “What is clear is that there is no observable increase in the number of strong tornadoes in the US over the past few decades,” adding: “Any role for climate change in affecting the conditions for tornado formation is still very much an open question and the subject of ongoing research by the scientific community.”

Finally, are there more black men in prison in the US than in colleges and universities? It’s a handy throwaway line for a speech emphasizing victimhood, but I picked that one apart very nicely about 5 years ago.

We can’t rely on the orators, advocates, media and advertisers to get it right. Use critical thinking. Question everything.

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