New study: Prevalence Rates of Male and Female Sexual Violence Perpetrators

UPDATE: I’ve become aware that the complete article I linked to isn’t available for free for everyone. Apparently a publicly funded organization in Norway called Helsebiblioteket (Health Library) have bought access to JAMA for everyone who has an IP adress that’s physically located in Norway. All the quoted text in the post below are from the actual paper and NOT from the National Geographic article I also linked to.

Michele L. Ybarra, MPH; Kimberly J. Mitchell, PhD Prevalence Rates of Male and Female Sexual Violence Perpetrators in a National Sample of Adolescents JAMA Pediatr. Published online October 07, 2013. doi:10.1001/jamapediatrics.2013.2629 available here:

This study found that females and males have carried out sexual violence at nearly equal levels by the age of 18 — 48 percent on the female side, 52 percent on the male side. 4% (10 females and 39 males) reported attempted or completed rape.

Other interesting findings:

females also appear to be more likely than males to engage in perpetration as part of a team or group: 2 of the 10 female perpetrators in this study engaged in group sexual assault compared with 1 of the 39 male perpetrators.

The term “sexual assault” means rape and attempted rape in this context (see the finding that 10 women and 39 men reported attempted or completed rape). I’ll write a bit about how this study appear to define rape later.

On victim blaming:

Fifty percent of perpetrators said that the victim was completely responsible; one-third (35%) said that they, the perpetrator, were completely responsible for the incident. Again, differences by perpetrators’ sex or age at first perpetration were not noted.

And the authors has this to say on challenging bias:

It is not uncommon to believe that a man cannot be raped by a woman. Gender stereotypes can make it difficult to imagine a dominant woman coercing or forcing an unwilling man to have sex. Accordingly, male victims of female perpetrators are judged more harshly than male victims of male perpetrators. Moreover, the same behaviors perceived to be sexually aggressive when committed by a male can be perceived as romantic or promiscuous when committed by a female. Nonetheless, physiological data suggest that men can be raped; an erection does not necessarily mean sexual arousal and can be reflexogenic. Adolescent health care professionals need to assess the potential for their own gender biases in this area so that they can be more effective in identifying and treating female perpetrators and male victims when they present.

In this National Geographic article about this paper Sharmili Majmudar of Chicago-based Rape Victim Advocates (which was not associated with the study) said that the paper also found that completed rape is predominantly a male crime—a finding that is in line with general attitudes about rape.

What I immediately ask myself then is how does the study define rape. They don’t state it outright in the paper, but they did write this:

Sexual violence perpetration was queried using 4 items. Three items were modified from the Sexual Experiences Survey and are consistent with the Bureau of Justice Statistics definition of rape, which can include “psychological coercion as well as physical force.”28

The reference (28) includes a link to a page on the BJS website.

Due to the the shutdown in the US the BJS website is currently unavailable, but the Wayback Machine has a cached version from May 2013 ( which states:

Rape – Forced sexual intercourse including both psychological coercion as well as physical force. Forced sexual intercourse means penetration by the offender(s). Includes attempted rapes, male as well as female victims, and both heterosexual and homosexual rape. Attempted rape includes verbal threats of rape.

By this definition a woman forcing a man to vaginal intercourse is NOT a forced sexual intercourse and hence NOT rape.

No wonder the paper found that men are the predominant perpetrators of rape if that’s the definition they’ve used.

Now, some of the language in other places in the paper makes me wonder whether they actually use the BJS definition in regards to the  “penetration” clause. I have contacted one of the authors Dr. Michele Ybarra to ask about this. This post will be updated if I get a reply.

Hat-tip to commenter OlaOla who in comment made me aware of this JAMA paper.


12 thoughts on “New study: Prevalence Rates of Male and Female Sexual Violence Perpetrators

  1. Hi Tamen, here’s a turn up for the books – me commenting on your blog for a change.

    I’ve been looking into this too, and asking some of the same questions – particularly the definition of rape.

    My hunch is that they are including forced to penetrate as rape, because otherwise I think it is unlikely they’d have found those proportions (ie 10 out of about 500 girls) admitting to it if it was excluding that.. My guess is they followed the usual methodology which would be to not use the word rape at all, but something like “forced someone to have sex even though they didn’t want to.”

    There are also another couple of things that jar for me – the statistic about ‘gang rape’ type activities strike me as so unusual I’m presuming its some kind of journalist’s mistake.

    But I’ve emailed the journal press office asking for a pdf of the paper, so if I get an answer before you I’ll let you know!

  2. Welcome Ally.

    My blog post and comment at your blog include a link to the complete paper published at JAMA in case you don’t want to wait for the PDF you’ve requested. The quote about “gang rape” isn’t from the newspaper article, but from the actual study itself.

  3. I’ve done some research and apparently a publicly funded organization called “Helsebiblioteket” (Health Library) in Norway have bought access to JAMA and some other journals making them accessible for anyone with an IP address that is physically located in Norway. I guess that is the reason why I see the complete article while you don’t. I’ll make a note of this at the end of the blog-post.

  4. I enjoyed reading all this. A good link suggested by OlaOla, a good blog post from Tamen and a good discussion with Ally Fogg. Like him, I’m jealous of the Norwegians – I think it’s a real problem when research and knowledge is restricted, especially when it was taxpayer-funded in the first place.

    The study here is very interesting. Their results suggest that victim-blaming is as common amongst female perpetrators as male perpetrators, and that almost equal numbers of girls and boys are sexually violent. Like Tamen, I’m also skeptical of the finding that attempted/completed rape is predominantly a male crime. Here are some more suggestions of how these results in particular might have been affected by bias in this study. (Although, note that I’ve not yet read the journal article so will have to go on Tamen’s excepts and the National Geographic’s summary.)

    Firstly, the reported figures for rape appear to be total lifetime prevalence. However, the abstract clearly states that (in their results) males started being sexually violent at earlier ages (or started reporting it at earlier ages?) and it was only in the 18-19 age group that equal perpetration emerged. So, what are the equivalent 18-19 age group figures for rape?

    The report investigates self-reported perpetration. Many studies have found that fewer women report sexual aggression than men report sexual victimisation by women. There could be many reasons for this. Perhaps women rapists have more victims per rapist than do male rapists. More likely, women are even less likely to perceive their aggression as unwanted than are men. And recall bias (or something similar) has been shown to be important when asking about experiences of sexual abuse: only 16% of men with documented medical histories of childhood sexual abuse volunteered that information when asked in a follow up study as adults. For these reasons, past-year incidence rates are more reliable imho than lifetime prevalence when discussing rape.

    Let’s also consider the questions used in this survey. We’re told that they used 4 questions to investigate sexual violence, 3 of which were modified from the Sexual Experiences Survey (SES). Well, are 4 questions enough? These 4 questions had to differentiate between sexual touching, attempted rape, completed rape. The questions were probably not very specific and this could introduce serious bias. Asking “have you ever raped someone?” will give different results to asking “have you ever forced someone to have sex against their will?” will give different results to asking “have you ever had sex with someone when they were unable to consent because they were intoxicated?” will give different results to… etc. The more specific the questions, the more people will recognise their own behaviour (or experiences). With only 4 questions, I doubt they were very specific here.

    Also note that the SES was invented by Mary Koss (and colleagues) and (from memory) does not include forced to penetrate as rape. In fact (from memory) the only way a woman can rape a man in the SES is to have forced anal sex with him. However, the researchers say they modified the SES and added an additional question, so we don’t know about this. Although the SES is still commonly used in many studies, and some previous studies have used a “modified SES” without correcting these methodological failings.

  5. Hi Santa, and welcome.

    Thanks for the link. That is an interesting study. Unfortunately I haven’t been able to locate a full and free version of it at the moment.

  6. In a comment on another post Santa provided this link:

    I’ll address it in this comment on this post since the link is talking about the survey/paper which is the subject of this post.

    The author (Eugene Volokh) writes a bit about how he thinks the categorization of rape is too wide. He seem to base that on the ways the manner of perpetration is categorized and also how the questions are asked and Volokh seem to disagree that a number of coercion strategies doesn’t qualify as rape. (I presume Volokh base this on the section on methodology in the paper). The thing is that the methodology section of the paper is pretty high-level and does not goes into much details.

    However, for the technically inclined I have doen some digging and a more detail description of the methodology and even the complete survey questionaire are available online in full.

    From the abstract of the paper:

    Data were collected online in 2010 (wave 4) and 2011 (wave 5) in the national Growing Up With Media study.

    The national Growing Up With Media study has it’s own homepage and on this page we find papers on the methodology for wave 4 and wave 5 as well as the complete questionaire for wave 4 and wave 5.

    The question about tactics were:
    Thinking about the most recent time you made someone have sex when they did not want you to, did you do it by….? Please select all that apply.

    • Arguing and pressuring this person over and over so they would say y
    • Making them feel guilty, swearing, getting angry or acting unhappy until you got your
    • Giving them alcohol or drugs
    • Threatening them
    • Using physical force
    • Being part of a group that made or tried to make this person have sex
    • Some other way, please specify:
    • Decline to answer

    (question Q3290 on page 87 on the wave 4 questionaire).

    Are there incidents where giving someone alcohol and then they decide to have sex with you which aren’t rape? Yes. However, if the person DOES NOT WANT to have sex with you and YOU MADE THEM have sex with you by giving them alcohol then I’d argue that it most likely is rape. Simply because we’re now not talking about buying a woman a beer or two and then she gets tipsy and horny and decide to have sex with you after all – that is not “MAKING THEM HAVE SEX” with you and I think the respondents pick up that difference. Had the survey asked “Did someone who initially didn’t want to have sex with you decide to have sex with you after you bought them X drink?” I think the objection from Volokh would’ve been more warranted. However, using the words “YOU MADE SOMEONE HAVE SEX” would exclude those cases.
    If you walked into a bar and chatted up a girl and asked her home for some goodtimes and she answered “No, I don’t want to have sex with you”. And then you bought her a couple of drinks and and she then said “You know, I think I’m in the mood after all – let’s go to your place”. Would you ever describe that as “making her have sex with you when ahw did not want to”?

  7. Pingback: Rape (And the Threat of Rape) Is A Crime of Violence, Not A Joke, or an Honor… | Dark Acts Bible: Glass Half Empty, Base Cracked...
  8. “Males were significantly more likely than females to report coercive sex or attempted rape, with similar but nonsignificant results observed for completed rape.”
    This is inside the study, so why do they say the opposite in the National Geographic?
    According to me it’s because they mix the ages.
    The study found that they were similar at 18-19 years, but not before (even if other studies find symmetry even in that age, if I well remember). If they count for all ages they’ll find more completed rape in males, but I think if they consider the age in which males and females become symmetric, I think they won’t find this difference.

Leave a Reply (first comment by first time commenters are auto-moderated - this might change when I get the hang of this and if the spam issue doesn't overwhelm me)

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s