In a report published by New York Times, an archaic definition of rape results in thousands of sexual assaults not being reflected in the federal government's crime report. The definition of rape used by the F.B.I. — “the carnal knowledge of a female, forcibly and against her will” — was written more than 80 years ago. This is far narrower than the definitions used by most police departments in U.S.

This old definition, critics say, does not take into account sexual-assault cases that involve anal or oral penetration or penetration with an object, cases where the victims were drugged or under the influence of alcohol or cases with male victims. As a result, many sexual assaults are not counted as rapes in the yearly federal accounting.

Law enforcement officials and advocates for women in U.S. say that this underreporting misleads the public about the prevalence of rape and results in fewer federal, state and local resources being devoted to catching rapists and helping rape victims. Rape crisis centers in USA cite the federal figures in applying for private and public financing.

The yearly report on violent crime, which uses data provided voluntarily by the nation's 18,000 law enforcement agencies, is widely cited as an indicator of national crime trends. According to the 2010 Uniform Crime Report, recently released by the FBI, there were 84,767 sexual assaults in the United States last year, a 5 percent drop from 2009.

In Chicago, the Police Department recorded close to 1,400 sexual assaults in 2010, according to the department’s Web site. But none of these appeared in the federal crime report because Chicago’s broader definition of rape is not accepted by the FBI. The New York Police Department reported 1,369 rapes, but only 1,036 — the ones that fit the federal definition — were entered in the federal figures.

In a recent survey conducted by the Police Executive Research Forum, almost 80 percent of the 306 police departments that responded said that the federal definition of rape used by the Uniform Crime Report was inadequate and should be changed.