This is a book about how the many charts—tables, graphs, maps, diagrams—we see every day through TV, newspapers, social media, textbooks, or advertising deceive us.
We’ve all heard the old idiom “A picture is worth a thousand words.” My hope is that you’ll soon stop using it unless you append it with this: “if you know how to read it.” Even common charts such as maps and bar graphs can be ambiguous or, worse, incomprehensible.
This is worrying because numbers are very persuasive, and so are charts, because we associate them with science and reason. Numbers and charts look and feel objective, precise, and, as a consequence, seductive and convincing.1
Politicians, marketers, and advertisers throw numbers and charts at us with no expectation of our delving into them: the average family will save $100 a month thanks to this tax cut; the unemployment rate is at 4.5%, a historic low, thanks to our stimulus package; 59% of Americans disapprove of the president’s performance; 9 out of 10 dentists recommend our toothpaste; there’s a 20% chance of rain today; eating more chocolate may help you win the Nobel Prize.2
The moment we turn on the TV, open a newspaper, or visit our favorite social media network, we are bombarded with flashy charts. If you have a job, your performance has likely been measured and shown through graphics. You may have designed them yourself to insert into slides for a class or business presentation. Some authors with a taste for the hyperbolic even talk about a “tyranny of numbers” and a “tyranny of metrics,” referring to the pervasiveness of measurement.3 As people in contemporary societies, we are easily seduced by our numbers and by the charts that represent them.
Charts—even those not designed with ill intent—can mislead us. However, they can also tell us the truth. Well-designed charts are empowering. They enable conversations. They imbue us with X-ray vision, allowing us to peek through the complexity of large amounts of data. Charts are often the best way to reveal patterns and trends hidden behind the numbers we encounter in our lives.
Good charts make us smarter.
But before that happens, we need to get used to perusing them with attention and care. Instead of just looking at charts, as if they were mere illustrations, we must learn to read them and interpret them correctly.
Here’s how to become a better chart reader.