The Data Detective: Ten Easy Rules to Make Sense of Statistics

by Tim Harford

Andrew Elliott—an entrepreneur who likes the question so much he published a book with the title Is That a Big Number?—suggests that we should all carry a few “landmark numbers” in our heads to allow easy comparison.[11] A few examples: The population of the United States is 325 million. The population of the United Kingdom is 65 million. The population of the world is 7.5 billion. Name any particular age (under the age of sixty). There are about 800,000 people of that age in the UK. If a policy involves all three-year-olds, for example, there are 800,000 of them. In the United States, there are about 4 million people of any particular age (under the age of sixty). Distance around the Earth: 40,000 kilometers, or 25,000 miles. It varies depending on whether you go around the poles or around the equator, but not much. The drive from Boston to Seattle: 3,000 miles. Length of a bed: 2 meters (or 7 feet). As Elliott points out, this helps you visualize the size of a room: How many beds is that? The gross domestic product of the United States: about $20 trillion (or $20,000 billion). It’s a lot of walls, if that’s really how you want to spend it. 100,000 words: the length of a medium-size novel. 1,454 feet: the height of the Empire State Building to its tip. (It’s also about 102 stories.)