"Lisak and Miller examined a random sample of 1,882 men, all of whom were students at the University of Massachusetts Boston between 1991 and 1998. Their average age was twenty-four. Of these 1,882 students, 120 individuals--6.4 percent of the sample--were identified as rapists, which wasn't a surprising proportion. But 76 of the 120--63 percent of the undetected student rapists, amounting to 4 percent of the overall sample--turned out to be repeat offenders who were collectively responsible for at least 439 rapes, an average of nearly 6 assaults per rapist. A very small number of men in the population, in other words, had raped a great many women with utter impunity. Lisak's study also revealed something equally disturbing: These same 76 individuals were also responsible for 49 sexual assaults that didn't rise to the level of rape, 277 acts of sexual abuse against children, 66 acts of physical abuse against children, and 214 acts of battery against intimate partners. This relative handful of male students, as Lisak put it, "had each, on average, left 14 victims in their wake....And the number of assaults was almost certainly underreported."