Quotes About Statistics

People are surprised to learn that if 23 people are in a room, the chances that two will share a birthday are better than even. With 57 in the room, the odds rise to 99 percent. Though it's unlikely that anyone in the room will share my birthday, we're not looking for matches with me, or with anyone else singled out a priori. We're counting matches post hoc, and there are 366 ways for a match to occur.

That tells us that the most damaging kinds of lethal violence (at least from 1820 to 1952) were murders and world wars; all the other kinds of quarrels killed far fewer people.

Finally, power-law distributions have "thick tails," meaning that they have a nonnegligible number of extreme values. You will never meet a 20-foot man, or see a car driving down the freeway at 500 miles per hour. But you could conceivably come across a city of 14 million, or a book that was on the bestseller list for 10 years, or a moon crater big enough to see from the earth with the naked eye—or a war that killed 55 million people.

So when one adjusts for population size, the availability bias, and historical myopia, it is far from clear that the 20th century was the bloodiest in history. Sweeping that dogma out of the way is the first step in understanding the historical trajectory of war.

The data are not entombed in dry reports but are displayed in gorgeous Web sites, particularly Max Roser's Our World in Data, Marian Tupy's HumanProgress, and Hans Rosling's Gapminder.

The top five countries that still execute people in significant numbers form an unlikely club: China and Iran (more than a thousand apiece annually), Pakistan, Saudi Arabia, and the United States. As in other areas of human flourishing (such as crime, war, health, longevity, accidents, and education), the United States is a laggard among wealthy democracies.

But probabilities are not about the world; they're about our ignorance of the world.

The peak age of poisoning deaths in 2011 was around fifty, up from the low forties in 2003, the late thirties in 1993, the early thirties in 1983, and the early twenties in 1973.57 Do the subtractions and you find that in every decade it's the members of the generation born between 1953 and 1963 who are drugging themselves to death.

The fact-checking site PolitiFact judged that an astonishing 69 percent of the public statements by Trump they checked were "Mostly False

Among the surprises in the statistics are that some things that sound exciting, like instant independence, natural resources, revolutionary Marxism (when it is effective), and electoral democracy (when it is not) can increase deaths from violence, and some things that sound boring, like effective law enforcement, openness to the world economy, UN peacekeepers, and Plumpy'nut, can decrease them.

how low it has sunk—to 10 percent. In two hundred years the rate of extreme poverty in the world has tanked from 90 percent to 10, with almost half that decline occurring in the last thirty-five years.

We live in a world not just with a smaller proportion of extremely poor people but with a smaller number of them, and with 6.6 billion people who are not extremely poor.

Of the seventy million people who died in major 20th-century famines, 80 percent were victims of Communist regimes

In the richest country two centuries ago (the Netherlands), life expectancy was just forty, and in no country was it above forty-five. Today, life expectancy in the poorest country in the world (the Central African Republic) is fifty-four, and in no country is it below forty-five.

When I surveyed perceptions of violence in an Internet questionnaire, people guessed that 20th-century England was about 14 percent more violent than 14th-century England. In fact it was 95 percent less violent.

Scandinavians needed a couple of additional centuries before they thought the better of killing each other, and Italians didn't get serious about it until the 19th century. But by the 20th century the annual homicide rate of every Western European country had fallen into a narrow band centered on 1 per 100,000.

Every statistics student is warned that "statistical significance" is a technical concept that should not be confused with "significance" in the vernacular sense of noteworthy or consequential.

The one great universal in the study of violence is that most of it is committed by fifteen-to-thirty-year-old men.

People in every country underestimate the proportion of their compatriots who say they are happy, by an average of 42 percentage points.

But if popular impressions are a guide, today's Americans are not one and a half times happier (as they would be if happiness tracked income), or a third happier (if it tracked education), or even an eighth happier (if it tracked longevity).

In the United States, Canada, and Australia, fewer than 3 percent of women report that their partners assaulted them in the previous year, but the reports from other countries are an order of magnitude higher: 27 percent in a Nicaraguan sample, 38 percent in a Korean sample, and 52 percent in a Palestinian sample.

The average American now retires at age 62. One hundred years ago, the average American died at age 51.

The writer Warwick Cairns calculated that if you wanted your child to be kidnapped and held overnight by a stranger, you'd have to leave the child outside and unattended for 750,000 years.211

For many people the greatest fear raised by the prospect of a longer life is dementia, but another pleasant surprise has come to light: between 2000 and 2012, the rate among Americans over 65 fell by a quarter, and the average age at diagnosis rose from 80.7 to 82.4 years.