After a long, drawn-out discussion, the FBI is definitely going to change its definition of rape from the old-fashioned "carnal knowledge of a female forcibly and against her will" to “penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim.” Significantly, this new definition will include male victims and victims who were subdued without threats or violence, usually because they were intoxicated or slipped drugs.*
These changes will likely have an impact on the annual crime statistics report the FBI releases, though it's hard to tell how dramatic. A substantial number of rapes involve male victims, as incidents such as the Penn State scandal demonstrate. Additionally, the old definition just so happened to exclude what may just be the most common kind of rape there is, rapes where the victim is subdued without threats or force. Research conducted by David Lisak and Paul M. Miller into what rapists themselves report doing shows that most avoid threats or force, presumably because both make a more clear-cut case of rape for police and juries. Your average rapist actually prefers to attack intoxicated women who are confused and struggle to fight back, presumably because they know few women report these cases and those who do rarely get very far with their cases. In fact, 60 percent of the rapists Lisak and Miller interviewed reported using this method. Rapists aren't stupid. They look at cases such as the one where two New York police officers were found not guilty of attacking a woman who had blacked out from drinking, and realize that this is a crime that is likely not to get you in any trouble.
Even with this new definition of rape, the annual FBI statistics will unfortunately still undercount the incidence of rape in this country. Many victims don't bother to report rapes, because the chance of social blowback and abuse from the legal system is high, and the chance of successfully putting the rapist in jail is low. A recent report from the CDC demonstrated that one in five American women and one in 71 men has endured a rape or attempted rape. This suggests that over a million women a year suffer rape or attempted rape, but in 2010, the FBI only reported 84,767 rapes reported to law enforcement under the old definition. Hopefully, this decision signals a new commitment to improve overall accuracy in collecting data on rape in America, helping us better learn how to fight it.
*Correction, December 16, 2011: The original version of this post incorrectly stated that the new rape definition excluded rape by object.