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Wind chill, and its pointlessness

Slate has this very interesting little essay about the "wind chill factor." For those not in the U.S. (or not living in the cold parts of the U.S.), you may not know about our obsession with this number. Typically, the weather report says the temperature is 25F but it "feels like" 10F (32 Fahrenheit is 0 Celsius). The "feels like" is temperature adjusted by the so-called "wind chill factor." It conveys the idea that keeping temperature constant, it feels colder when there is wind. The Slate article covers a bunch of general issues related with inventing metrics: People love large numbers, in this case, because we are measuring cold temperatures, they like really small numbers The name of the metric may have little or nothing to do with what is being measured In seeking to make numbers more palatable to the public, people may choose less precise language that sometimes completely loses the original meaning. For example, "feels like" does not indicate that wind is at issue. Other factors like humidity also affect how cold one feels, at constant temperature. That said, the public is hungry for statistical concepts or metrics that can be explained easily and understood instinctively. There is nothing wrong with this desire. After a metric is established, it's not easy to dislodge it. Changing the metric renders the entire history useless. I also made this point in the chapter on obesity metrics in Numbersense (link). How cold one feels is affected by a system of multiple factors, including temperature, wind, humidity, etc. Any definition of the perceived temperature involves the notion of statistical adjustments For more, read the Slate essay.    

from Big Data, Plainly Spoken (aka Numbers Rule Your World) http://bit.ly/2TiluZr
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