It’s everywhere, really. Please learn to recognize it.

Numeracy is the “ability to understand and work with numbers” in order to “use maths in everyday life”, for a better understanding of the world.

Anumeracy is the opposite, that is lack of numeracy.

Anumeracy is bad, and I just met it

The graph above represents the membership of an organization, from 2011 to 2021. I saw it by chance, because someone posted it online, worrying that the organization may never recover for such a steep loss. He wrote, more or less: “a 10% decrease in membership in one year! If this is confirmed, it’s a meltdown!"

Two readers explicitly accused him of catastrophism, and of having some hidden agenda, because:

1. The [meltdown-like] slope of that curve in the graphic is just a consequence of how you set the scales on the axes. Numbers are important but they must be used better than that
2. Hey, [if that is your agenda]… why don’t you just zoom the Y axis even more, so the drop in membership will look even bigger?

Comments like those are perfect examples of anumeracy. Those concerns maybe unfounded, but if one thing is sure is that it is just dumb to treat them as an optical illusion, that would disappear if the chart were drawn differently.

Because what that chart shows is a 10% drop from 2020 to 2021. And a 10% drop in one year is a 10% drop in one year… no matter how you draw axes. It is, that is, a trend that, were it constant, would cancel any organization in less than ten years, regardless of its age and initial size. But even if it were limited to one year only, it would be serious anyway.

Anumeracy is always bad. In a society where everything is digital and measured, is much more dangerous. In a moment when recovery of society depends on wide understanding of how the rates of mask adoption, vaccination and other parameters… is even more toxic.

This is why I am really worried because of anumeracy, and so should you. Because comments like those show that it is really everywhere.

Images source: Wikimedia Commons