In other words, Obama cited a government study that came up with a number of females raped or sexually assaulted that was at least five times higher than another government survey. It was also twice as high as the prevalence number for rapes estimated by the 1989-1990 National Women’s Study and 30 percent greater than yet another survey, the 1995 National Violence Against Women Study.
However, the Justice Department survey has long been criticized as an inadequate measure of rape. A National Research Council report in 2014 offered recommendations on how to improve it, saying it was “highly likely” it was underestimating the number of rapes. While the NRC report made no judgment on the CDC survey — since that was not part of its mandate — the panel noted how much higher the numbers were in the CDC report: “This differential between the NISVS and the other surveys is surprising.”
“We were surprised to see how much larger the CDC estimates were than other surveys, but unfortunately given the data we had from them we could not thoroughly explore this,” said Candace Kruttschnitt, a University of Toronto professor who was co-chair of the NRC panel.
Both surveys were drawn from many interviews. The Justice Department survey was based on interviews with more than 143,000 people, with a response rate of 88 percent. The CDC study was based on interviews with more than 14,000 people, with a response rate of 33 percent.
The Justice Department survey is a classic example of a criminal justice approach. It asked how someone was attacked, and if rape was mentioned, the survey asked a series of questions about the incident. By reference, the actual number of reported forcible rapes and attempted rapes was under 85,000 in 2012. So even under this approach, researchers uncovered far more rapes than are reported.
The questions in the CDC survey are much more open-ended, never using terms such as rape or sexual assault. The full questionnaire is embedded at the end of this column, but here’s an example of one section. The first part is the introduction, which is then followed by the actual question in bold.