Pointers on the Zero Point (à la Jonah Goldberg)

August 5, 2018
Posted by Jay Livingston

As cheap tricks in data visualization go, leaving out the zero point is one of the easiest and most common ways to make a molehill of difference appear to be a mountain. Here’s an example I’ve used before — the Fox News graph showing that a tax rate 39.6% is five times the size of a tax rate of 35%

(Click on an image to enlarge it.)

I’ve blogged on this before (here and here), and as some of the comments on those posts argue, cutting the y-axis down to size is not always deceptive. But in most cases, it’s good to include the zero-point.

Jonah Goldberg, the conservative political writer, has learned that lesson. Sort of. Philip Cohen, in his review (here) of Goldberg’s latest book Suicide of the West: How the Rebirth of Tribalism, Populism, Nationalism, and Identity Politics is Destroying American Democracy, has provided examples of Goldberg’s data-viz facility. The problem: how to exaggerate effects while yet including the zero point. Goldberg’s solution: simple – just truncate the y-axis as usual, but then stick a label of zero on the lowest point.

From these graphs we learn
  • In 1960, life expectancy worldwide was nearly 0.
  • By 2015, infant mortality worldwide had decreased to nearly 0
In a mere 55 years, we went from a world where nearly all infants died to a world in which almost no infants died.

As Philip Cohen notes, the book’s blurbs from conservative pals and colleagues (e.g., John Podhoretz, Arthur Brooks) mention Golberg’s “erudition.” Apparently, this erudition stops short of knowing that the distance between 54 and 56 is not the same as the distance between 0 and 54.

1 comment:

David J Littleboy said...

There's an XKCD follow up to this: