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Knowing the Numbers: How Bad Sex-Offender Data Could Cause More Harm
Knowing the Numbers: How Bad Sex-Offender Data Could Cause More Harm

JURIST Guest Columnist Jill Levenson of Lynn University criticizes the reliance of the Supreme Court and others on inaccurate sex offender data…

In the US Supreme Court’s recent decision upholding sex offender registration requirements (SORNA) under the Adam Walsh Act [PDF], the Court’s opinion [PDF] included the following statement: “SORNA’s general changes were designed to make more uniform what had remained “a patchwork of federal and 50 individual state registration systems … with loopholes and deficiencies” that had resulted in an estimated 100,000 sex offenders essentially disappearing off law enforcement’s radar.

It is astounding that in this age of widespread information and access to research, the Court is relying on inaccurate statistics. The commonly repeated statistic of 100,000 missing sex offenders is often erroneously attributed to the National Center for Missing and Exploited Children or the US Marshals Service, both of which continue to proclaim on their websites that 100,000 sex offenders are missing — despite published evidence to the contrary. This misinformation is frequently included in congressional testimony and in media reports, influencing social policy, public opinion and funding allocations.

A study published in 2012 disputed the claims that 100,000 registered sex offenders in the US are “missing.” The study, conducted by University of Massachusetts Lowell criminologist Andrew Harris and myself, was published in the scientific journal Criminal Justice Policy Review. It analyzed data downloaded directly from online sex offender registries in 2010 and also surveyed states’ registry managers.

The study utilized a sample of more than 445,000 registered sex offenders listed on public registries. Harris and I were able to identify sex offenders designated by states to be transient, homeless, absconded, non-compliant or whose address or whereabouts were otherwise unknown. Nationwide, about 2.4 percent were officially listed as absconded, unable to be located or non-compliant with registration mandates. When including those designated as homeless or transient, the rate grew to slightly over four percent.

Using the more liberal four percent figure to estimate the number of sex offenders living in the community whose whereabouts could not be verified, the count was calculated to be somewhere between 23,000 and 30,000. The study emphasized that these numbers included technical non-compliance as well as true absconding. Ultimately, no evidence was found to support the frequently repeated statistic that 100,000 (or about fourteen percent) of the nation’s sex offenders are missing or unaccounted for.

Harris and I also reported on data obtained in 2010 via e-mail and telephone surveys of state registry managers. Rates of registration non-compliance among registrants living in the community varied greatly, ranging from about one percent in some states (e.g., Florida, Minnesota, Iowa, Missouri, North Dakota, Vermont and West Virginia) to approximately thirteen percent in others (California, Hawaii and Oklahoma). Nationally, the median rate of non-compliance is about 2.7 percent. The variation in how state systems defined and categorized offenders made it difficult to estimate exactly how many sex offenders have truly gone missing.

Policymakers and courts should make decisions armed with current, published, peer-reviewed research utilizing appropriate methodologies. Those providing testimony (especially federally funded agencies) should be expected to inform legislative bodies, courts and media with current and credible data. To do otherwise breaches the public trust.

Dr. Jill Levenson is an Associate Professor of Psychology and Social Sciences at Lynn University in Boca Raton, FL. Recognized internationally as an expert on sexual aggression and sex crime policy, she has published over eighty peer-reviewed articles and book chapters and has co-authored three books on the treatment of sex offenders and their families.

Suggested citation: Jill Levenson, Faulty Data Must Not Influence Sex Crime Policy, JURIST – Hotline, July 3, 2013,

This article was prepared for publication by Michael Muha, an associate editor with JURIST’s professional commentary service. Please direct any questions or comments to him at

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