ZOMBIE STATISTICS: The terrifying power of useful bad data.

• Author: Mangu-Ward, Katherine
• Position: FUTURE

"YOU'RE ABOUT TO be untricked," boasted the opening line of a groundbreaking 1981 Reason investigation about high-profile chemical leaks in upstate New York. In the early '80s, Love Canal had already become synonymous with corporate willingness to destroy the environment and human health in the name of profit. But careful reporting revealed the anti-corporate narrative was wrong; the primary malefactor wasn't the greedy businessmen at Hooker Chemical but the Niagara Falls Board of Education, which developed a plot of land despite many warnings from Hooker about the presence of dangerous chemicals. Unfortunately, Reason's story did little to change the anti-market tenor of the environmental reforms that followed.

That's because when a narrative is powerful and useful to highly motivated activists, it can be fiendishly difficult to roll it back. Zombie statistics, in particular, are tough to defeat. These undead tidbits can sustain incredible blows and yet continue to crawl forward, like the plodding, inexorable zombies in George Romero's Night of the Living Dead--a film that debuted in 1968, the same year as Reason. These raggedy facts terrorize the debates over important issues for years after they have been definitively debunked.

At a time when #MeToo and Title IX are dominating the headlines, for instance, it can seem like sexual assault is everywhere. But one of the central statistics responsible for that perception rests on an astonishingly weak foundation. You've probably heard this shocking figure: One in five women has been sexually assaulted while in college.

One of the sources of support for that number is a 2002 study by David Lisak, who concluded that what had previously been referred to as "date rape" was actually the result of repeated infractions by serial campus predators. Lisak urged administrators to view every accusation "as an opportunity to identify a serial rapist," a way of thinking that in turn validates harsh treatment for accused students and justifies funding a massive bureaucracy for adjudication. The Obama White House cited Lisak in memoranda, anti-rape activists promoted his work in movies and books, and university administrators invited him to give lectures and sit on panels.

But as Davidson College administrator Linda M. LeFauve explained in our pages three years ago, Lisak's study was based on survey data cobbled together from his students' dissertations and masters' theses. The central data set drew from...