Bad Statistics: USA Today
Not suprisingly, bad statistics can be found in almost any daily issue of USA Today, one publisher’s attempt at a newspaper for the masses (which I often read while travelling, since it is free… you get what you pay for, I suppose). In a story today, Is ‘failure to launch’ really a failure?, the writer (and headline editors) suggest that there’s a significant growing trend of children living at home with their parents in their mid-20’s. They trot out some researchers to prove their point, of course, and mention a few statistics that also seem to make their case:
High housing costs are only part of the reason young adults are staying home in greater numbers than ever before.
Since 1970, the percentage of people ages 18 to 34 who live at home with their family increased 48%, from 12.5 million to 18.6 million, the Census Bureau says.
That’s a great number, the kind of number reporters love to grab a hold of — 48%! Wow, if that’s not a trend over 36 years, I don’t know what is!
Of course, absent context, numbers only tell the story the writer wants them to tell. If you don’t put a number in context, it is a nugget of information that means virtually nothing. I was in a meeting the other week with the great Saul Wurman who told a great story that illustrates the lunacy of some of the data we’re presented with in our everyday lives. He noted, for instance, that the pilot on an airplane loves to come on the intercom to let you know when you’ve reached cruising altitude, usually around 32,000 feet or so. But why tell you that number? What’s its context? How high is 32,000 feet and why should you, as a passenger, care? Why not tell you the cruising speed? Or outside temperature? It’s like the pilots all held a meeting and said, “So what useless piece of information should we throw out today?” Without context or comparison, the information — although true and accurate — is without meaning to most people.
Wurman tells another great example — How large is an acre? Most people couldn’t tell you. They know their house sits on 1.4 acre, but don’t really know how large that is. But tell a person, “An acre of land is approximately the size of a football field without the end zones,” and most people then “get it.” Information in context or comparison to something most people know or understand, well, that becomes meaningful then.
So in this piece on USA Today, of course I trust these numbers are accurate, fact-checked, wonderful numbers. But the unspoken fact that doesn’t accompany these numbers if that the population of the U.S. has also increased in the past 36 years. The question then becomes, well, how much has the U.S. population increased since 1970?
In 1970, the U.S. Census Bureau reports there were approximately 204 million Americans. In 2006, the estimate is approximately 297 million Americans. That’s an approximate 32% increase in our population in the past 36 years. So if we substract the normal population growth from the USA Today article percentages, 48 – 32 = 16. Wow. A 16% increase. Not nearly so interesting a number. And over 36 years, hardly an astounding trend that needs to be reported on today.
What else was going on in 1970 that may have also affected that number?
Well, the U.S. was involved in a war in Vietnam, if memory serves correctly, which drafted a lot of those people in the 18 to 34 year old category. So maybe that number in 1970 is artificially low (although one could argue we’re also involved in a war now, but of course today, there’s no draft).
So what motivates USA Today to publish a story of this nature? Well, the connection to the new movie, “Failure to Launch,” seems like the obvious answer. The thinking probably goes something like this, “Wow, that’s a funny story in that movie, I wonder if that’s really happening in the U.S. today.” The writer digs up a few numbers that seem to confirm the trend, without bothering to look at context, and proceeds to write a whole story around this “trend.” And voila! A dozen more pieces will surely follow in online publications and other newspapers reinforcing the “trend.”
It’s okay to publish numbers and statistics to illustrate your point. Just make sure you get them right and account for normal growth and such. Especially if it appears to be a premise of the article.
Grohol, J. (2006). Bad Statistics: USA Today. Psych Central. Retrieved on June 26, 2016, from http://psychcentral.com/blog/archives/2006/03/16/bad-statistics-usa-today/