Successful Prediction

Successful prediction is the revenge of the nerds. Superforecasters are intelligent but not necessarily brilliant, falling just in the top fifth of the population. They are highly numerate, not in the sense of being math whizzes but in the sense of comfortably thinking in guesstimates. They have personality traits that psychologists call “openness to experience” (intellectual curiosity and a taste for variety), “need for cognition” (pleasure taken in intellectual activity), and “int...

 Risk of Childhood Kidnapping are Very Low

A generation ago 70 percent of children played outside; today the rate is down to 30 percent.209 In 2008 the nine-year-old son of the journalist Lenore Skenazy begged her to let him go home by himself on the New York subway. She agreed, and he made it home without incident. When she wrote about the vignette in a New York Sun column, she found herself at the center of a media frenzy in which she was dubbed “America’s Worst Mom.” (Sample headline: “Mom Lets 9-Year-Old Take Subway Home A...

 Buddhini Samarasinghe: Scientists Should Stick to Science

It is a statistical fact that you are more likely to die while horseback riding (1 serious adverse event every ~350 exposures) than from taking Ecstasy (1 serious adverse event every ~10,000 exposures). Yet, in 2009, the scientist who said this was fired from his position as the chairman of the UK's Advisory Council on the Misuse of Drugs. Professor David Nutt's remit was to make scientific recommendations to government ministers on the classification of illegal drugs based on the harm they c...

 PETWHAC

PETWHAC stands for Population of Events That Would Have Appeared Coincidental. Population may seem an odd word, but it is the correct statistical term. I won't keep using capital letters because they stand so unattractively on the page. Somebody's watch stopping within ten seconds of the psychic's incantation obviously belongs within the petwhac, but so do many other events. Strictly speaking, the grandfather clock's stopping should not be included. The mystic did not claim that he could stop...

 The Law of Large Numbers

The game is called who’s the best at flipping coins. It’s pretty simple. You flip a bunch of coins and whoever gets the most heads wins. To make this a little more interesting, though, not everybody has the same number of coins. Some people—Team Small—have only ten coins, while the members of Team Big have a hundred each. If we score by absolute number of heads, one thing’s for almost sure—the winner of this game is going to come from Team Big. The typical Big player is going to ...

 Correlation != Causation; However, It is Often All We Have

> correlation doesn't mean causation. As a statistician, I guess I should be happy that more people are aware of this. But I also think too many people are taking "correlation != causation" superficially. I mean, almost all of science is based on significant correlational findings, especially when the traditional way to prove causation (i.e. via randomized trial) is unethical (i.e. we can't randomly assign people to be insured vs. uninsured). Along these lines, I often find people who sa...

 Gompertz Law of human mortality

What do you think are the odds that you will die during the next year? Try to put a number to it — 1 in 100? 1 in 10,000? Whatever it is, it will be twice as large 8 years from now. This startling fact was first noticed by the British actuary Benjamin Gompertz in 1825 and is now called the “Gompertz Law of human mortality.” Your probability of dying during a given year doubles every 8 years. For me, a 25-year-old American, the probability of dying during the next year is a fairly ...

 The Cost of Irrational Fears

Imagine the typical emotional reaction to seeing a spider: fear, ranging from minor trepidation to terror. But what is the likelihood of dying from a spider bite? Fewer than four people a year (on average) die from spider bites, establishing the expected risk of death by spider at lower than 1 in 100 million. This risk is so minuscule that it is actually counterproductive to worry about it: Millions of people die each year from stress-related illnesses. The startling implication is that the r...

 The Pareto Distribution

The Pareto distribution shows up in a remarkably wide array of complex systems. Together, “the” and “of” account for 10 percent of all words used in English. The most volatile day in the history of a stock market will typically be twice as volatile as that of the second-most volatile and ten times the tenth-most. Tag frequency on Flickr photos obeys a Pareto distribution, as does the magnitude of earthquakes, the popularity of books, the size of asteroids, and the social connectedness...

 Card Trick Involving Chance

A good card magician knows many tricks that depend on luck—they don’t always work, or even often work. There are some effects—they can hardly be called tricks—that might work only once in a thousand times! Here is what you do: You start by telling the audience you are going to perform a trick, and without telling them what trick you are doing, you go for the one-in-a-thousand effect. It almost never works, of course, so you glide seamlessly into a second try—for an effect that works...