Darrell Huff published How to Lie with Statistics in 1954. But something else happened that very same year: two British researchers, Richard Doll and Austin Bradford Hill, produced one of the first convincing studies to demonstrate that smoking cigarettes causes lung cancer.
Doll and Hill could not have figured this out without statistics. Lung cancer rates had increased sixfold in the UK in just fifteen years; by 1950 the UK had the highest in the world, and deaths from lung cancer exceeded deaths from tuberculosis for the first time. Even to realize that this was happening required a statistical perspective. No single doctor would have formed more than an anecdotal impression.
As for showing that cigarettes were to blame—again, statistics were essential. A lot of people thought that motorcars were the cause of the rise in lung cancer. That made perfect sense. In the first half of the twentieth century, motorcars became commonplace, with their exhaust fumes and the strangely compelling vapor from the tar in new roads. Lung cancer increased at the same time. Figuring out the truth—that it was cigarettes rather than cars that caused lung cancer—required more than simply looking around. It required researchers to start counting, and comparing, with care. More concisely, it required statistics.
The cigarette hypothesis was viewed with skepticism by many, although it was not entirely new. For example, there had been a big research effort in Nazi Germany to produce evidence that cigarettes were dangerous; Adolf Hitler despised smoking. The Führer was no doubt pleased when German doctors discovered that cigarettes caused cancer. For obvious reasons, though, "hated by Nazis" was no impediment to the popularity of tobacco.
So Doll and Hill decided to conduct their own statistical investigations. Richard Doll was a handsome, quiet, and unfailingly polite young man. He had returned from the Second World War with a head full of ideas about how statistics could revolutionize medicine. His mentor, Austin Bradford Hill, had been a pilot in the First World War before nearly dying of tuberculosis.* Hill was a charismatic man, had a sharp wit, and was said to be the finest medical statistician of the twentieth century. Their work together as data detectives was to prove lifesaving.
The pair's first smoking-and-cancer study began on New Year's Day 1948. It was centered around twenty hospitals in northwest London, and Richard Doll was in charge. Every time a patient arrived in a hospital with cancer, nurses would—at random—find someone else in the same hospital of the same sex and about the same age. Both the cancer patients and their counterparts would be quizzed in depth about where they lived and worked, their lifestyle and diet, and their history of smoking. Week after week, month after month, the results trickled in.
In October 1949, less than two years after the trial began, Doll stopped smoking. He was thirty-seven, and had been a smoker his entire adult life. He and Hill had discovered that heavy smoking of cigarettes didn't just double the risk of lung cancer, or triple the risk, or even quadruple the risk. It made you sixteen times more likely to get lung cancer.
Hill and Doll published their results in September 1950, and promptly embarked on a bigger, longer-term, and more ambitious trial. Hill wrote to every doctor in the UK—all 59,600 of them—asking them to complete a "questionary" about their health and smoking habits. Doll and Hill figured that the doctors would be capable of keeping track of what they smoked. They would stay on the medical register, so they'd always be easy to find. And when a doctor dies, you can expect a good diagnosis as to the cause of death. All Hill and Doll had to do was wait.
More than 40,000 doctors responded to Hill's request, but not all of them were delighted. You have to understand that smoking was extremely common at the time, and it was no surprise to find that 85 percent of the male doctors in Doll and Hill's initial sample were smokers. Nobody likes to be told that they might be slowly killing themselves, especially if the suicide method is highly addictive.
One doctor buttonholed Hill at a London party. "You're the chap who wants us to stop smoking," he pointedly declared.
"Not at all," replied Hill, who was still a pipe smoker himself. "I'm interested if you go on smoking to see how you die. I'm interested if you stop because I want to see how you die. So you choose for yourself, stop or go on. It's a matter of indifference to me. I shall score up your death anyway."
Did I mention that Hill originally trained as an economist? It's where he learned his charm.
The study of doctors rolled on for decades, but it wasn't long before Doll and Hill had enough data to publish a clear conclusion: Smoking causes lung cancer, and the more you smoke the higher the risk. What's more—and this was new—smoking causes heart attacks, too.