Factfulness: Ten Reasons We're Wrong About the World – and Why Things Are Better Than You Think

How to Control the Gap Instinct
There are three common warning signs that someone might be telling you (or
you might be telling yourself) an overdramatic gap story and triggering your
gap instinct. Let’s call them comparisons of averages, comparisons of
extremes, and the view from up here.
Comparisons of Averages
All you averages out there, please do not take offense at what I am about to
say. I love averages. They are a quick way to convey information, they often
tell us something useful, and modern societies couldn’t function without
them. Nor could this book. There will be many averages in this book. But any
simplification of information may also be misleading, and averages are no
exception. Averages mislead by hiding a spread (a range of different numbers)
in a single number.
When we compare two averages, we risk misleading ourselves even more
by focusing on the gap between those two single numbers, and missing the
overlapping spreads, the overlapping ranges of numbers, that make up each
average. That is, we see gaps that are not really there.
Look at the two (unrelated) graphs here, for example:

---

The graph on the left shows the gap between the average math scores of
men and women taking SAT tests in the United States, for every year since
1965. The graph on the right shows the gap between the average income of
people living in Mexico and the United States. Look at the huge differences
between the two lines in each graph. Men versus women. United States versus
Mexico. These graphs seem to show that men are better at math than women,
and that people living in the United States have a higher income than
Mexicans. And in a sense this is true. It is what the numbers say. But in what
sense? To what extent? Are all men better than all women? Are all US
citizens richer than all Mexicans?
Let’s get a better sense of the reality behind the numbers. First, let’s change
the scale on the vertical axis. Using the same numbers, we now get a very
different impression. Now the “gap” seems almost gone.
Now let’s look at the same data in a third way. Instead of looking at the
averages each year, let’s look at the range of math scores, or incomes, in one