Sex assault statistics tell varying stories

Experts say data can be misread, create confusion
Liz Hardin, center left, an emergency department nurse, and Joanne Knuppe, center right, an obstetrics nurse, watch forensic nurse Kim Nash trim Emma Agnew’s fingernails as Nash leads a training session for Sex Assault Forensic Exams in Colorado Springs. For the training, Agnew portrayed a woman who had been assaulted.

The account in December in Rolling Stone magazine of a gang rape at the University of Virginia capped a year in which sexual assault on campus gained traction as a national issue.

The White House published a list of institutions under federal investigation for mishandling sexual violence, released recommendations for colleges and resources for students and launched a public awareness campaign, “It’s On Us.”

And then the Rolling Stone story collapsed. Key details in the account of the UVA student didn’t hold up to scrutiny by The Washington Post, and critics began questioning the statistic that one in five college women are assaulted.

So what’s the truth? Rocky Mountain PBS I-News analyzed research on sexual assault among college students.

Parsing the statistics

Are one in five college women assaulted? That number is based on a 2007 Campus Sexual Assault study conducted by RTI International and funded by the Institute of Justice. An online survey from 6,800 students at two large public institutions found that one in five senior women had experienced a completed sexual assault in college.

Controversy about the study has focused on its small scope – it’s not nationally representative.

Rich Lowry, of the National Review, called the number “bogus” because it includes things such as attempted forced kissing.

That’s not true, Krebs said, and reflects a misreading of the data. The one-in-five number includes only completed sexual assaults, not attempts.

If you look at only completed rapes, Krebs said, the headline from the CSA study is that one in seven of the seniors in the study was raped.

Studies with substantially different methods and scopes have come up with substantially different results. Most recently, a December 2014 analysis of the National Crime Victimization Survey by the Bureau of Justice Statistics estimated the rate of rape and sexual assault among college women (from 1995 to 2013) at 6.1 per 1,000 in the previous 12 months.

So why the discrepancy? There are big methodological differences.

The first is the time span. The NCVS study measures victimization rate per 12 months, versus the entire four- or five-year span of college assessed in the CSA study.

Second, the NCVS is focused on assessing rates of crime. Callie Rennison, of the University of Colorado-Denver and a former staff member at the Bureau of Justice Statistics, said that means the survey probably misses some rapes and sexual assaults.

“The fact that it’s a crime survey means that if you don’t think what happened to you is a crime, you may not be willing to tell me about it,” Rennison said.

The problem, she said, is that misperceptions about rape – that it’s an act committed by a stranger with a weapon, for example – are common even among its victims.

How frequent is false reporting?

False reporting happens. You can find estimates varying widely from less than 1 percent to 40 percent and higher. But some of the research showing high rates of false reporting crumbles under scrutiny.

Men’s-rights groups frequently cite a 1994 study conducted by former Purdue University sociologist Eugene Kanin, using 109 rape allegations made to the police department of a small Midwestern city from 1978 to 1987. Kanin found that 41 percent of the cases were false, based on the determinations of police officials. In all those cases, he said, the accusers recanted their allegations.

David Lisak, a former psychology professor at the University of Massachusetts-Boston, has written that the study “violates a cardinal rule of science” by failing to describe Kanin’s efforts to evaluate the criteria of the police department.

He also questions the practice of asking accusers to undergo a polygraph – which has been outlawed in many states because it can intimidate victims into recanting their allegations.

Other studies have based their conclusions on police departments’ determinations that rape cases are “unfounded.” But “unfounded” isn’t the same as a “false report” and can include cases in which a person recounts an incident that may not fit the definition of rape.

One of the most recent and transparent studies on false reporting was published in 2014 by Arizona State University criminologist Cassia Spohn and two co-authors. They analyzed 81 unfounded rape cases from the L.A. Police Department in 2008 and estimated that 4.5 percent of the reports were false.

Despite the low rate of false reporting, few sexual assaults result in a criminal conviction. There’s no national database that tracks rape reports to their final outcomes.

“This is a major problem with our criminal justice statistics,” said Spohn, the Arizona State University criminologist.