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Matt DeLisi would argue that the phrase “things are not what they seem” appropriately describes the impetus for his latest study, “The Dark Figure of Sexual Offending: A Replication and Extension.” DeLisi, Distinguished Professor in Liberal Arts and Sciences and College of Liberal Arts and Sciences Dean’s Professor, published the research last October in the journal Behavioral Sciences and the Law. His findings suggest that sexual offenders of even minor offenses are likely capable of committing more severe sexual crimes than their official records indicate.

The dark figure of sexual offending concept contends that there is a significant amount of hidden sexual violence among sexual offenders with no official criminal history. In other words, a high percentage of individuals who have been arrested for non-contact sexual offenses, like possession of child pornography, for example, have actually engaged in prior sexual contact with at least one victim, and sometimes many more.

This theory is nothing new to DeLisi. In 2016, he and colleagues with federal probation conducted a study of 119 federal sexual offenders who self-reported an average of 3.69 sexual contact victims; some admitted to having up to 24 victims. Overall, 69% of those offenders disclosed sexual contact victims who were not included in their official criminal records.

“So many times, a child porn possession case will have no official criminal history, which would justify potentially supervising them as low risk,” DeLisi said. “What we find, though, is that the majority of them have prior contact victims. So even though they have no official criminal history, not only do they have actual prior crimes, but they have actual prior contact sexual offenses.”

Replication matters

DeLisi felt compelled to conduct a second study about the dark figure of sexual offending to give credence to his original study and others like it. He teamed up with two colleagues, Alan Drury, assistant teaching professor in Iowa State’s Department of Sociology who also works at the U.S. Probation and Pretrial Services, Southern District of Iowa; and Michael Elbert, also with the U.S. Probation and Pretrial Services, Southern District of Iowa, to determine if a new group of correctional clients would support the results of their 2016 study.

“We wanted to know was this just an abnormality in our sample that was either high or low. For instance, the true prevalence could be 10% or 90%, we’re not sure. So, the more studies that keep being published that find that it’s 50-75%, that gives us confidence that this is true scientifically,” he said.

The latest study

Their latest study comprised 216 federal offenders who were on supervised release between 2016 and 2020. Of the 216, 109 (50.5%) had an official arrest charge for a sexual contact offense and 107 (49.5%) did not. The top three most common offenses of this group included possession or receipt of child pornography, noncompliance with the Sex Offender Registration and Notification Act and distribution of child pornography.

For the 2020 study, DeLisi implemented two different procedures to collect data about the corrections clients to determine correlations between certain characteristics and their sexual offenses. First, information from the clients’ federal case management tracking system were extracted and tracked in a database. That data included variables such as demographics and other assorted case information. Second, DeLisi analyzed data from the clients’ pre-sentence investigation report, Bureau of Prisons documents, psychological and psychiatric reports, treatment records, criminal career indicators and self-reported sexual history.

As a part of their supervised release, correction clients are required to participate in polygraph tests to determine if they have participated in activity that is against their release conditions.

“What we find is when the polygraph examiners capture these indications of deception and follow up with them, more often than not, the offenders will divulge their truth and say, yes, I’ve had these numbers of victims, this is their gender, their age, when it occurred, things of that sort, sometimes in really frightening detail,” DeLisi said.

Disturbing results

Of the 216 offenders in DeLisi’s latest study, 73.8% admitted to previous sexual abuse, which is consistent with the 2016 study (69%). Also, 59% of the offenders who were charged with possession or distribution of child pornography, considered a low-risk offense, admitted to previously committing sexual abuse. One offender reported 25 victims.

“There’s a large number of offenders with a great deal of victimization, and that’s just the number of victims,” DeLisi said. “That’s not capturing potentially how many victimizations occurred, which could be a one-off occurrence or it could be hundreds to thousands of events.”

DeLisi is not surprised by the results, partly because his and other previous studies support these numbers. But he also understands, through significant research, that most criminals have likely committed more crimes than their arrest records reveal.

“A person’s criminal history is just a sampling of their actual behavior,” he said.

Cause for concern

DeLisi said the data replication in this study affirms that sexual offenders of even minor offenses are likely capable of committing numerous sexual crimes that will forever traumatize their victims.

“Any kind of trauma is bad—physical abuse, physical neglect, medical neglect—they are all bad. But none of them can compare to sexual abuse as a form of trauma in terms of the lifelong impairments that it causes,” DeLisi said. “If a boy is sexually abused, the likelihood that he will also be a sexual offender is extremely high. In girls, they tend to internalize the victimization, so you see high levels of psychiatric disturbance, substance abuse and suicidal behaviors.

“The stakes of that potential form of contact are so severe and high that we take it very seriously,” DeLisi added. “The most stringent way we can supervise these clients and guard against any of those victimizations occurring is going to go a long way to reduce sexual abuse in society, so that’s incredibly important.”

DeLisi hopes this study will promote further research into the dark figure of sexual offending, and that all federal jurisdictions will increase their supervision of sexual offenders, including those with no official prior criminal histories.

“There are two broad ways you can react to this population,” DeLisi said. “One is in favor of crime control, victims and public safety, which is the view I and my fellow authors have. The other view is that it’s not a severe crime because it’s only online behavior and they have no criminal history, so therefore you are being unjustified in viewing them as a higher risk. That is not our view.”