Section 2: The Nature and Scope of Sex Offending
40 Minutes


Use SlideUse Slide #1: Understanding Sex Offenders: An Introductory Curriculum

As a starting point, I’d like to ask you a few questions about sexual victimization.

Generally—when these and other kinds of questions are posed about this topic— people offer a wide range of responses, but their answers aren’t necessarily consistent with what is found in the literature.  And that applies not only to some members of the general public, but also can be the case with some who work in this field. 

In this section I am going to provide a general overview of sexual victimization—its incidence and prevalence, known reporting rates, and a few basic trends pertaining to these kinds of offenses. And then I will highlight some general information about the sex offenders who come to the attention of the authorities. Having a broad sense for this information is a crucial first step in understanding this serious problem and considering how best to respond to it.

Use SlideUse Slide #2: Incidence and Prevalence
Use SlideUse Slide #3: Age of Victims
Use SlideUse Slide #4: Gender of Victims
Use SlideUse Slide #5: Age of Victims by Gender
Use SlideUse Slide #6: Victim/Offender Relationship by Age
Use SlideUse Slide #7: Reporting Rates
Use SlideUse Slide #8: Reasons for Not Reporting

Incidence and Prevalence of Sexual Victimization

Sexual assault is a widespread occurrence. According to the National Violence Against Women Survey, approximately 302,100 women and 92,700 men are forcibly raped in the United States each year.1 It is estimated that one in six women and one in 33 men in the United States have experienced an attempted or completed rape sometime in their lives.2 Similarly, approximately one in four girls and one in seven boys are sexually assaulted before the age of 18.3

Age of victims

In fact, many sexual assaults are committed against our nation’s youth. In the National Violence Against Women Survey, over half of the respondents who experienced an attempted or completed rape reported that the assault occurred when they were under 18 years of age.4 Yet another national survey found the same trend, with 61% of reported rapes occurring before the victim reached age 18.5

These numbers are also replicated in official crime reporting data, which reflects the reporting rates of sexual assaults to law enforcement agencies across the country. For example, according to the National Incidence Based Reporting System, roughly two thirds—or 67%—of all victims of reported sexual assaults were under 18 years of age. And more than half of these victims were under the age of 12.6 These numbers are striking, aren’t they?

Gender of victims

As you may have noticed from some of the statistics I just mentioned, women and girls are particularly vulnerable to sexual assault. According to official reports, they are more than six times as likely as males to be victimized sexually.7 And whereas the chances of a male being targeted decrease as he enters into adolescence and beyond, the chances of a female being sexually victimized actually increase as they move from childhood to adolescence, peaking at around the age of 14.8

Victim–offender relationship

Another particularly important finding is that most victims of sexual abuse know the person who abuses them. In fact, when we look at the data, only a relatively small percentage of perpetrators are strangers to their victims.9 In both rape and child sexual abuse cases, most of the offenders are either family members or acquaintances.

When you think about these various statistics about sexual victimization, what is your reaction? What—if anything—surprises you about them?

Even for those of us who work in this field, some of these trends can be surprising, and we actually have fairly good access to this information. Unfortunately, those in our communities—as well as other important stakeholders—may not receive this kind of data, and sometimes, they may hear inaccurate or misleading information, which may lead them to believe in commonly held myths or misperceptions about sex crimes, victims, and the individuals who commit these offenses. For example, the information about the relationship between victims and offenders is probably not commonly known by many people in the general public. All too often, they may subscribe to the myth that victims of sex crimes are generally targeted by strangers. Again, that’s in part the result of a lack of comprehensive and ongoing community education efforts around this critical issue. Instead, people tend to hear about a few very tragic and “high profile cases” in which strangers commit heinous crimes, often against children; and in the absence of the full “picture” of sexual victimization, they understandably make assumptions or draw conclusions about these crimes. But as you have now seen, those kinds of cases are not reflective of the actual victimization trends and what we know.

Under–reporting of sexual victimization

The issue about what we “know” about victims and offenders raises another important point. A significant problem with statistics and other information that we have about these crimes is that they are limited by what is known to the authorities. In others words, they are based only on the cases that are reported. And unfortunately, sexual assault is perhaps the most underreported crime.10

In fact, researchers have found that the majority of victims of sexual assaults—about 84%—do not report their victimization to law enforcement.11

Can you think of any reasons why this might be the case? In other words, why might someone choose not to report their sexual victimization to police?

(Possible answers include: the victim is afraid to report the assault; the victim feels like they provoked the assault; the victim may feel ashamed.)

Yes, there are many reasons that sexual victimization goes unreported. Some victims do not report it to police because they believe nothing can be done or because they worry that there may not be enough proof. They might also choose not to report these crimes out of fear of retaliation by the offender, or because they or their loved ones were threatened. And in some cases, particularly intrafamilial child sexual abuse or domestic partner rapes, the victims may have strong attachments to the abusers, may want to protect them, may be emotionally or financially dependent on them, may not want the family to be disrupted, or may not want them to be punished.

Sexual victimization is a very personal matter, and many who have been victimized simply do not want to discuss it with others—especially someone that they don’t know. And similarly, some victims may be concerned about others finding out about what happened to them. Not only might a person who has been victimized already feel as though they are somehow responsible, but they may also worry that others will blame them for what happened. Or they may worry that law enforcement officials—or even their own friends, family, or loved ones—will not believe what happened to them was really an assault; in fact, some victims may wonder about this very issue themselves.

Male victims of sexual assault may face additional concerns about reporting their victimization to police and are, as a result, less likely to report their sexual victimization.12 Whereas the average rate of reporting sexual assault for females is approximately 17%,13 some experts estimate the average rate of reporting sexual assault for males is as low as 5%.14 Male victims who are targeted by male perpetrators may fear that if they disclose their sexual victimization to police and others, others might question their sexual orientation or identity, their masculinity, or their strength for not stopping the attack. And if the offender was female, male victims may worry that others will question how they could possibly be victimized by a female, which may be in part related to biases within our society about the potential for women to commit sex offenses. Regardless of the gender of the offender, male victims—similar to female victims—may often question their own response to the attack, as well.

At any rate, it is clear that victims—both male and female—do not always view reporting their sexual victimization as a safe or worthwhile option, and therefore they may never disclose their abuse.

So what does this mean for those of us who are involved in this work?

(Possible answers include: we are only aware of a fraction of the sexual assaults that actually occur; we underestimate not only the rate of sexual violence against all victims, but male victims in particular; we are not able to catch or apprehend the offenders of these crimes; we know very little about the offenders of these crimes.)

All of the issues that you mentioned are valid issues for us to consider.

(Trainer should repeat or summarize participants’ responses back to the group.)

So we must always keep in mind that we only know what we know—the data about victims and victimization that we are working with only reflects what has been reported. And that applies to what we know about those who commit these crimes as well.

Sex Offenders Who Come to the Attention of the Authorities

Because sexual abuse is such a hidden crime, the individuals who commit sex offenses often remain hidden to us, too. Let’s talk for a few minutes, then, about what we know about sex offenders—at least those who come to the attention of the criminal justice system.

Arrests of sex offenders

Use SlideUse Slides #9–11: Arrests of Sex Offenders
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Use SlideUse Slide #12: Arrests by Offense Type
Use SlideUse Slide #13: Convicted Sex Offenders

In 2004, there were 26,066 arrests for forcible rape and 90,913 arrests for other sex offenses in the United States.15 Adults account for about 80% of these arrests, although a considerable percentage are juveniles.16 And as you can see, males account for approximately 95% of arrests for sex crimes.17

Now, if you consider for a moment arrests for all different types of crimes, what percentage do you think are represented by sex offenses specifically?

The answer may surprise you. The data indicates that arrests for sex offenses account for less than 1% of all arrests.18 Although arrests for sex offenses represent a very small proportion of arrests for all crimes, the absolute numbers of both offenders and victims—and the considerable impact that sex offenses have on victims, families, and communities—are still profound. And of course, we are only talking about the number of people who were actually arrested for these crimes. Again, we only know what is reported. And even if an incident is reported, not all of those reports actually lead to an arrest.

Convicted sex offenders

Just as not all reported incidents lead to an arrest, not all arrests actually result in a criminal conviction. So when we consider the sex offenders who are currently in the criminal justice system—either those who are incarcerated or those under criminal justice supervision in the community, we know that we are only seeing a small fraction of the individuals who have committed these offenses. In fact, some would suggest that they represent only the tip of the iceberg.

Nonetheless, the population of sex offenders entering our nation’s prisons has grown substantially in recent years. Remember that sex offenses represent only 1% of arrests for all crimes. Yet it is estimated that between 10 and 30% of our prison populations are comprised of sex offenders.19  Arriving at a precise number can be difficult because of the different ways in which studies identify offenders and define sex offenses, but based on recent prison census data, it can be conservatively estimated that over 150,000 sex offenders are incarcerated in state and federal correctional facilities throughout the country.20 In fact, from 1980 to 1994, the number of incarcerated sex offenders increased by 300%.21

Sometimes, when members of the general public and even some professionals hear about the high percentages and large numbers of incarcerated sex offenders, they are relieved because these offenders are “off the streets,” so to speak. However, in reality, almost all offenders—at least 97% – will eventually return to our communities.22 This equates to as many as 20,000 sex offenders being released into local communities each year.23

Using recent data about offenders under probation or parole supervision in the United States, and taking into account previous figures for sex offenders under community supervision specifically, it is estimated that roughly 170,000 sex offenders may be under community supervision at the present time.24 The number of sex offenders who are actively under the supervision of criminal justice authorities is believed to represent only about 10% of all sex offenders living in our communities, however.25 That’s because many known sex offenders have already completed their probation or parole requirements, and again, many individuals who have committed sex offenses have not been detected or apprehended in the first place.

Officially undetected offenses

Up to this point, we’ve reviewed some of the basic information and trends that come from official crime reports and victimization data on record. But there are some additional sources of data that can help us understand even more about these offenders and their behaviors. Specifically, researchers have been able to learn from the offenders themselves about other sexually deviant behaviors—and even additional sex crimes—that have gone undetected.26 If reliable, this information suggests that the “picture” of the offender that we get when we look at official records may not reflect the full picture, and challenges the myth that the sex offense for which an individual is convicted is the only offense that he has committed.

For example, in a very influential study by Abel and his colleagues, several hundred sex offenders were granted federal assurances of confidentiality so that they could disclose to the researchers their full sex offense histories without the possibility of that information being reported to law enforcement. 27 On average, these offenders admitted to having many more victims and offenses than were known to the authorities. Another study by Freeman–Longo and Blanchard yielded strikingly similar results, with significantly greater numbers of undetected deviant sexual acts than what were indicated in the official records for these offenders.28 Something else that was very noteworthy in this particular study was that some rapists of adult women reported that they had also committed sex offenses against children, and some child sexual abusers reported that they had also perpetrated rapes against adult women. This is referred to as “crossover.” In other words, beyond what we learn about the actual numbers of undetected offenses and victims, we might also learn that there are additional types of deviant or criminal sexual behavior and the types of victims may be different than what is documented in official records. Some individuals have demonstrated problems with sexual deviance across categories of offending behaviors, such as engaging in rape of an adult women and the molestation of young children.

All of these findings are consistent with some of the more recent work of practitioners who use the polygraph in the sex offender management process—particularly as a means of facilitating disclosures of offenders’ sexual histories.29 As a result, we have gained additional insights into the possibilities for undetected sex offenses, and we are more aware that the sex crimes for which individuals are arrested and ultimately convicted may not be their first or only sex offenses. In fact, published studies involving the polygraph have revealed that the data found in official records may reflect a significant under–indication of the extent and range of individuals’ sex offending behaviors.30

Taken together, these studies demonstrate how—compared to official records—we may glean a much fuller picture of sex offenders based on their own self disclosure. But why do you think this information is important? What does it tell us?

Use SlideUse Slide #14: Convicted Sex Offenders

What this suggests is that we need to fully understand the sex offenders with whom we are working, and that we need to get as complete a “picture” of them as we can in order to be most effective in our work. There may be more than simply meets the eye, so to speak. Therefore, we can’t simply base any of our decisions on a single document or single piece of information, whether that is a police report, other record, or an offender’s self report. Comprehensive assessment information about each individual offender will help us determine how to respond and intervene most appropriately and responsibly.

Recidivism rates

Before we wrap up this section, I’d like to spend just a moment highlighting what we know about recidivism—commonly measured by new arrests or new convictions—of those sex offenders who come to the attention of the authorities.

When I asked you earlier about what percentage of sex offenders is known to reoffend, a number of different estimates were offered. What do you think that the general public believes the recidivism rate is?

Use SlideUse Slide #15: Undetected Offenses
Use SlideUse Slides #16–17: Observed Recidivism Rates Over Time
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Contrary to public perception and common myths that exist about sex offenders, recidivism rates for sex offenders are relatively low. For example, some of the most recent research, looking at thousands and thousands of sex offenders—some treated, some not, some who were incarcerated, some who were not—reveals an average recidivism rate of less than 15% over a 5–6 year follow–up period.31 Not surprisingly, when following them for longer periods of time, the rates go up to some extent. For example, in one study that followed approximately 4,700 sex offenders, the recidivism rate of the group as a whole was 14% at the 5 year follow–up, 20% at the 10 year follow–up, and 24% after 15 years of follow–up.32

You should know, however, that recidivism rates for sex offenders can vary significantly depending upon a number of variables, including the types of victims they target and whether they have been convicted of prior sex offenses and the types of victims they target.33 As a group, the individuals with prior convictions for sex crimes had higher rates of sexual recidivism than those without a prior sex crime conviction.  And as you can see, in that same study, those who committed sex offenses within the family (incest offenders) had the lowest rates of recidivism over time, and those who molested male children outside of the family had the highest rates.

Also noteworthy is that the overall recidivism rate for sex offenders is lower than that of other criminal populations—both for violent and non–violent offenders.34 In fact, sex offenders—when they are arrested or convicted again—tend to have committed non–sex crimes rather than new sex offenses.35 But again, we must always keep in mind that these numbers represent only those offenses detected by the authorities. And even though these observed rates of recidivism are relatively low, we must remember the impact that additional sex offenses have on victims, families, and communities can be very significant.

Thus, it is critical that we do what we can to prevent further victimization. Learning more about victims and offenders, gaining additional information about crime trends, understanding offense characteristics, and researching issues related to recidivism—as these studies have done—can help us to do just that.


We’ve covered a lot of data and statistics in this section in order to offer you a sense for the nature and extent of this challenging issue. Taken together, these statistics and some of the research we’ve reviewed suggest that our knowledge of the scope of sex offending and victimization is, by no means, complete. Nonetheless, we have to work within the parameters of what we do know, and we need to develop interventions, strategies, and policies that are informed by the best information available—even though it may be limited—rather than attempting to address the problem of sex offending based on myths or misinformation.

In the next section, we will consider what the available research and professional literature indicates about what sex offenders “look like,” which will further help us understand what we know about this population and the implications for our work in this field.

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