In a new column at the Daily Beast, Eleanor Clift notes that the numbers being cited for campus rapes may be wrong.

Is the Campus Rape Crisis Overblown?

The finding that one in five women are sexually assaulted in college is as widely known as it is startling. Countless media reports repeat and recycle the alarming statistic, and it headlined the initial report introduced by Vice President Biden from the White House Task Force to Protect Students from Campus Assault.

But how trustworthy is that figure of one in five? An earlier poll found it was more like 1 in 40, but should it matter whether the real number is closer to the high or low end of the scale?

“We know there are rapists on campus that target vulnerable women,” says Christina Hoff Sommers, a resident scholar at the conservative American Enterprise Institute, who thinks getting the numbers right is important. “Inflated figures lead to ineffective policies and breed panic and over-reach.”

Sommers makes a good case that the one-in-five finding is inflated, and that the administration and the media have been careless in disseminating it as fact. It comes from a 2007 study conducted by the Justice Department’s National Institute of Justice, a web-based survey of two large public universities, one in the Midwest, and one in the South. Female undergraduates aged 18 to 25 took part in the anonymous random sample, and each received a $10 certificate to Amazon for participating.

Web surveys are automatically suspect, and the response rate was less than half, 42 percent, “which is miserable,” says Sommers. The researchers themselves cautioned against over-generalizing from the 5,446 respondents to the entire country’s college population, and Sommers cites the danger of selection bias, where people who feel most strongly respond.