The typical rape victim is young, unmarried and from a low-income family. Her assailant is usually an unarmed stranger who attacks her between the hours of 6 p.m. and midnight, most often away from her home. Half of the rape victims do not report the crime.

These are among the key findings of a new Justice Department study that is the first in-depth look at the estimated 1.5 million rapes or attempted rapes that occurred between 1973 and 1982. Rape, according to the study, accounts for about 3 percent of all violent crimes. An estimated 154,000 rapes or attempted rapes occurred in 1983, involving roughly one out of every 600 women 12 years of age or older.

Women in the 16 to 24 age group were two to three times more likely to be victims of rape or attempted rape than women in general, and black women were a disproportionately high percentage of victims. Half of the victims had family incomes of under $10,000 a year.

The study found that women were twice as likely to be assaulted by strangers as by someone they knew, but only slightly more inclined to report the former attack than the latter.

Assistant Attorney General Lois Haight Herrington, who heads the department's Office of Justice Programs, is convinced that rape victims are not reporting the crime in a large measure because victims are "treated so outrageously." Herrington, who chaired the President's Task Force on Victims of Crime, said almost 1,000 people gave testimony in one form or another to the task force and "almost every victim said, 'Don't report it, it's not worth it.' "

Rape victims, she says, often have to pay for the crime. Literally. "We found that 22 to 28 states require the victim to pay for the forensic examination cost . . . . We don't do this to burglary victims," she says. The department has given a grant to the Center for Women's Policy Studies to develop model legislation for states to correct this.

Furthermore, in many states the addresses of rape victims are given to defense attorneys, which increases the victim's fear of reprisal, particularly if she was not attacked in her home. "There's no reason to do this," says Herrington.

Convictions continue to be undermined by sloppy, uninformed investigative work in many areas of the country, with valuable evidence being destroyed, she says. And finally, wide judicial discretion in sentencing results in an average incarceration time for rape of less than three years, which she says "is terrible. It's a terrible crime that many times affects not just the victim but all family members. I do not think that less than three years is a sentence commensurate with the harm done to women."

A conference was held last year at the FBI Academy that brought experts on rape from across the country together and produced both information and recommendations that could lead to more reporting and higher conviction rates for the crime. The National Association of States' Attorney Generals, for example, agreed to draft model legislation for states so that the victim's address is not given out.

"We found the FBI Academy now has a laser technique that takes a fingerprint off the neck. When we can take fingerprints off the neck and we can say these are strangulation marks, the issue of consent goes out the window. That must be made known to everybody," says Herrington. There have also been major breakthroughs in "genetic markings," she says, through which blood and secretion analysis can lead to positive identification of the assailant. Findings from the conference will soon be available to law enforcement officials throughout the country.

Victims of sexual assault and family violence have top priority in the distribution of up to $100 million allocated by Congress last year to help crime victims. Half of the fund, financed by federal criminal fines, will go to states to help compensate victims for medical bills and lost wages, and the other half will go to victim assistance programs such as rape crisis centers.

These centers, usually staffed by volunteers and operating on a shoestring, have performed a pivotal role in helping rape victims deal with the crime and the law enforcement system. Better funding for them, increased training for the staff on such matters as protecting evidence, can only lead to better conviction rates. That, combined with various other steps the Justice Department is taking, ought to help persuade more and more women to report the crime. As long as silence is the refuge of the victim, the rapist is safe.