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If you put an o on understo, you’ll ruin my thunderstorm.

Paul Alper writes:

Here is a fascinating article by Matthew Cappucci from the Washington Post dealing with the difficulty experts have when trying to convey technical results to the lay public.

In a nutshell, the categories the experts at the Storm Prediction Center use:

marginal, slight, enhanced, moderate or high

do not correspond to the linguistic feelings of the general public, the intended audience of the typical TV/radio weather forecaster:

It’s been shown time and time again, however, that the general public doesn’t understand the categories. Is a slight risk or a marginal risk more significant? And why is moderate risk not in the middle? What’s an enhanced risk? Meteorologists know the system like the back of their hand. But the public does not.

A student, Alex Forbes, at Mississippi State University gathered the following data. It shows that the public is all over the linguistic map when it comes to ordering and interpretation of the terms used.

From the above graphic, “High” is the only category in which the experts and the general public are in agreement.

As part of his project, Forbes asked nearly 4,000 respondents to rank the presumed order of the SPC’s five categories based on their implied severities. On the whole, respondents got 4 out of the 5 categories wrong.

“The SPC outlook was never meant for public consumption,” he said. “It still isn’t to this day. The only reason it’s published is because [the SPC is] required to by federal law as a federal agency.”

According to Patrick Marsh, chief of science support at NOAA’s Storm Prediction Center the problem of misinterpretation began when:

After reviewing feedback from emergency management, they broke it into three categories: marginal, slight, and enhanced. That’s when public confusion really ramped up.
“There is no real word that fits between ‘slight’ and ‘moderate’ that works,” Marsh said. “‘Enhanced’ showed a little bit more promise. But SPC knew there was going to be a problem there. The words aren’t perfect.”

Sean Ernst, a student at the University of Oklahoma points out that the SPC terminologies

“were never designed necessarily with the general public in mind.”

“You can have a perfectly accurate forecast,” Ernst said, “but a forecast has no value unless a user can make an educated decision based on it.”

Obviously, this problem of miscommunication between experts and the lay public is not confined to weather forecasting. The term “statistically significant” comes readily to mind. As does “peer review,” “margin of error” and many others. So, how to do better when defining terms in order to communicate with the general public?

I’m reminded of the saying, “It’s harder to do the wrong thing right than to do the right thing right.”

Also, the numbers in the table above should be rounded to the nearest percentage point. “38.6%,” indeed.

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