In a 2007 campaign advertisement, former New York City mayor Rudy Giuliani said, “I had prostate cancer, five, six years ago. My chances of surviving prostate cancer—and thank God, I was cured of it—in the United States? Eighty-two percent. My chances of surviving prostate cancer in England? Only 44 percent under socialized medicine.” Giuliani used these statistics to argue that he was lucky to be living in New York and not in York. This statement was big news. As we will explain, it was also a big mistake.

Knowing Your Chances: What Health Stats Really Mean: Scientific American