Case studies are singular examples that seem to illustrate a phenomenon. Textbooks would be dull without them, and journalists often use interviews to add color to their stories. But case studies can become so alluring, and seem to illustrate interesting patterns so well that they can encourage us to draw conclusions without further investigation.
Take the case of Kitty Genovese, a 28-year-old woman who was stabbed to death in Queens, New York, in 1964. Her case gained notoriety because there were purportedly dozens of witnesses to the attack who did not call the police. This led researchers to study something they called the bystander effect, positing that the more people who observe an event take place, the less likely they are to take action because they presume that someone else will.