Polling about Holocaust denial has created horror and consternation on multiple occasions, offering lessons applicable to polling more broadly. In probably the most widely reported poll finding of 1992, more than one in five Americans (22 percent) doubted the Holocaust had occurred, with another 12 percent unsure. Survivor Eli Weisel was aghast. “What have we done?” the late Nobel Laureate lamented to a reporter. “I’m shocked that 22%–oh my Gd.” More than a year later, it became clear that 22 percent was a significant exaggeration resulting from a poorly worded question. Posed by the Roper Organization, the question asked, “Does...